The following is a list of Major League Baseball players, retired or active. As of the end of the 2011 season, there have been 320 players with a last name that begins with O who have been on a major league roster at some point.
| Name | Debut | Final game | Position | Teams | Ref |
|---|---|---|---|---|---|
| Mike O'Berry | April 8, 1979 | October 4, 1985 | Catcher | Boston Red Sox, Chicago Cubs, Cincinnati Reds, California Angels, New York Yankees, Montreal Expos | [1] |
| Billy O'Brien | September 27, 1884 | October 3, 1890 | First baseman | St. Paul Saints, Kansas City Cowboys (UA), Washington Nationals (1886–1889), Brooklyn Gladiators | [2] |
| Bob O'Brien | April 11, 1971 | July 7, 1971 | Pitcher | Los Angeles Dodgers | [3] |
| Buck O'Brien | September 9, 1911 | August 6, 1913 | Pitcher | Boston Red Sox, Chicago White Sox | [4] |
| Charlie O'Brien | June 2, 1985 | June 21, 2000 | Catcher | Oakland Athletics, Milwaukee Brewers, New York Mets, Atlanta Braves, Toronto Blue Jays, Chicago White Sox, Anaheim Angels, Montreal Expos | [5] |
| Cinders O'Brien | June 23, 1888 | October 2, 1891 | Pitcher | Cleveland Blues, Cleveland Spiders, Cleveland Infants, Boston Reds (AA) | [6] |
| Dan O'Brien | September 4, 1978 | September 28, 1979 | Pitcher | St. Louis Cardinals | [7] |
| Darby O'Brien | April 16, 1887 | October 15, 1892 | Outfielder | New York Metropolitans, Brooklyn Bridegrooms/Grooms | [8] |
| Dink O'Brien | April 26, 1923 | September 15, 1923 | Catcher | Philadelphia Phillies | [9] |
| Eddie O'Brien | April 25, 1953 | April 19, 1958 | Shortstop | Pittsburgh Pirates | [10] |
| George O'Brien | August 16, 1915 | August 23, 1915 | Catcher | St. Louis Browns | [11] |
| Jack O'Brien (C) | May 2, 1882 | September 16, 1890 | Catcher | Philadelphia Athletics (AA), Brooklyn Grays, Baltimore Orioles (AA) | [12] |
| Jack O'Brien (OF) | April 14, 1899 | September 28, 1903 | Outfielder | Washington Senators (NL), Cleveland Blues (AL), Boston Americans | [13] |
| John O'Brien (OF) | April 19, 1884 | May 31, 1884 | Outfielder | Baltimore Monumentals | [14] |
| John O'Brien (2B) | April 22, 1891 | October 7, 1899 | Second baseman | Brooklyn Grooms, Chicago Colts, Louisville Colonels, Washington Senators (NL), Baltimore Orioles (NL), Pittsburgh Pirates | [15] |
| Johnny O'Brien | April 19, 1953 | July 19, 1959 | Second baseman | Pittsburgh Pirates, St. Louis Cardinals, Milwaukee Braves | [16] |
| Pete O'Brien (1890s 2B) | August 2, 1887 | June 16, 1890 | Second baseman | Washington Nationals (1886–1889), Chicago Colts | [17] |
| Pete O'Brien (1900s 2B) | September 21, 1901 | October 2, 1907 | Second baseman | Cincinnati Reds, St. Louis Browns, Cleveland Naps, Washington Senators | [18] |
| Pete O'Brien (1B) | September 3, 1982 | July 20, 1995 | First baseman | Texas Rangers, Cleveland Indians, Seattle Mariners | [19] |
| Ray O'Brien | June 27, 1916 | July 12, 1916 | Outfielder | Pittsburgh Pirates | [20] |
| Syd O'Brien | April 15, 1969 | October 1, 1972 | Third baseman | Boston Red Sox, Chicago White Sox, California Angels, Milwaukee Brewers | [21] |
| Tom O'Brien (2B) | June 14, 1882 | July 28, 1890 | Second baseman | Worcester Ruby Legs, Baltimore Orioles (AA), Boston Reds (UA), New York Metropolitans, Rochester Broncos | [22] |
| Tom O'Brien (OF) | May 10, 1897 | October 13, 1900 | Outfielder | Baltimore Orioles (NL), Pittsburgh Pirates, New York Giants | [23] |
| Tommy O'Brien | April 24, 1943 | May 13, 1950 | Outfielder | Pittsburgh Pirates, Boston Red Sox, Washington Senators | [24] |
| Danny O'Connell | July 14, 1950 | September 26, 1962 | Second baseman | Pittsburgh Pirates, Milwaukee Braves, New York/San Francisco Giants, Washington Senators (1961–1971) | [25] |
| Jimmy O'Connell | April 17, 1923 | September 28, 1924 | Outfielder | New York Giants | [26] |
| John O'Connell (2B) | August 22, 1891 | September 20, 1902 | Second baseman | Baltimore Orioles (AA), Detroit Tigers | [27] |
| John O'Connell (C) | August 16, 1928 | October 6, 1929 | Catcher | Pittsburgh Pirates | [28] |
| Pat O'Connell | July 22, 1886 | September 9, 1886 | Outfielder | Baltimore Orioles (AA) | [29] |
| Andy O'Connor | October 6, 1908 | October 6, 1908 | Pitcher | New York Highlanders | [30] |
| Brian O'Connor | May 13, 2000 | September 27, 2000 | Pitcher | Pittsburgh Pirates | [31] |
| Dan O'Connor | June 3, 1890 | July 19, 1890 | First baseman | Louisville Colonels | [32] |
| Frank O'Connor | August 3, 1893 | August 7, 1893 | Pitcher | Philadelphia Phillies | [33] |
| Jack O'Connor (C) | April 20, 1887 | October 9, 1910 | Catcher | Cincinnati Red Stockings (AA), Columbus Solons, Cleveland Spiders, St. Louis Perfectos/Cardinals, Pittsburgh Pirates, New York Highlanders, St. Louis Browns | [34] |
| Jack O'Connor (P) | April 9, 1981 | October 3, 1987 | Pitcher | Minnesota Twins, Montreal Expos, Baltimore Orioles | [35] |
| Johnny O'Connor | September 16, 1916 | September 16, 1916 | Catcher | Chicago Cubs | [36] |
| Michael O'Connor | April 27, 2006 | Pitcher | Washington Nationals, New York Mets | [37] | |
| Paddy O'Connor | April 17, 1908 | July 22, 1918 | Catcher | Pittsburgh Pirates, St. Louis Cardinals, Pittsburgh Rebels, New York Yankees | [38] |
| Darren O'Day | March 31, 2008 | Pitcher | Los Angeles Angels of Anaheim, New York Mets, Texas Rangers | [39] | |
| Hank O'Day | May 2, 1884 | October 3, 1890 | Pitcher | Toledo Blue Stockings, Pittsburgh Alleghenys, Washington Nationals (1886–1889), New York Giants, New York Giants (PL) | [40] |
| Ken O'Dea | April 21, 1935 | August 6, 1946 | Catcher | Chicago Cubs, New York Giants, St. Louis Cardinals, Boston Braves | [41] |
| Paul O'Dea | April 19, 1944 | September 20, 1945 | Outfielder | Cleveland Indians | [42] |
| Billy O'Dell | June 20, 1954 | September 12, 1967 | Pitcher | Baltimore Orioles, San Francisco Giants, Milwaukee/Atlanta Braves, Pittsburgh Pirates | [43] |
| George O'Donnell | April 18, 1954 | July 25, 1954 | Pitcher | Pittsburgh Pirates | [44] |
| Harry O'Donnell | April 30, 1927 | September 30, 1927 | Catcher | Philadelphia Phillies | [45] |
| John O'Donnell | July 16, 1884 | July 16, 1884 | Catcher | Philadelphia Keystones | [46] |
| John O'Donoghue (1960s P) | September 29, 1963 | June 22, 1971 | Pitcher | Kansas City Athletics, Cleveland Indians, Baltimore Orioles, Seattle Pilots, Milwaukee Brewers, Montreal Expos | [47] |
| John O'Donoghue (1990s P) | June 27, 1993 | October 3, 1993 | Pitcher | Baltimore Orioles | [48] |
| Lefty O'Doul | April 29, 1919 | September 30, 1934 | Outfielder | New York Yankees, Boston Red Sox, New York Giants, Philadelphia Phillies, Brooklyn Robins/Dodgers | [49] |
| Bob O'Farrell | September 5, 1915 | September 23, 1935 | Catcher | Chicago Cubs, San Francisco Giants, St. Louis Cardinals, Cincinnati Reds | [50] |
| Eric O'Flaherty | August 16, 2006 | Pitcher | Seattle Mariners, Atlanta Braves | [51] | |
| Hal O'Hagan | September 24, 1892 | July 17, 1902 | First baseman | Washington Senators (NL), Chicago Orphans, New York Giants, Cleveland Bronchos | [52] |
| Greg O'Halloran | May 16, 1994 | August 6, 1994 | Catcher | Florida Marlins | [53] |
| Bill O'Hara | April 15, 1909 | May 8, 1910 | Outfielder | New York Giants, St. Louis Cardinals | [54] |
| Kid O'Hara | September 15, 1904 | September 22, 1904 | Outfielder | Boston Beaneaters | [55] |
| Tom O'Hara | September 19, 1906 | July 4, 1907 | Outfielder | St. Louis Cardinals | [56] |
| Charley O'Leary | April 14, 1904 | September 30, 1934 | Shortstop | Detroit Tigers, St. Louis Cardinals, St. Louis Browns | [57] |
| Dan O'Leary | September 3, 1879 | August 6, 1884 | Outfielder | Providence Grays, Boston Red Caps, Detroit Wolverines, Worcester Ruby Legs, Cincinnati Outlaw Reds | [58] |
| Troy O'Leary | May 9, 1993 | September 28, 2003 | Outfielder | Milwaukee Brewers, Boston Red Sox, Montreal Expos, Chicago Cubs | [59] |
| Ryan O'Malley | August 16, 2006 | August 22, 2006 | Pitcher | Chicago Cubs | [60] |
| Tom O'Malley | May 8, 1982 | October 3, 1990 | Third baseman | San Francisco Giants, Chicago White Sox, Baltimore Orioles, Texas Rangers, Montreal Expos, New York Mets | [61] |
| Ollie O'Mara | September 8, 1912 | April 19, 1919 | Shortstop | Detroit Tigers, Brooklyn Robins | [62] |
| Tom O'Meara | September 29, 1895 | July 22, 1896 | Catcher | Cleveland Spiders | [63] |
| Randy O'Neal | September 12, 1984 | October 2, 1990 | Pitcher | Detroit Tigers, Atlanta Braves, St. Louis Cardinals, Philadelphia Phillies, San Francisco Giants | [64] |
| Skinny O'Neal | April 18, 1925 | May 27, 1927 | Pitcher | Philadelphia Phillies | [65] |
| Denny O'Neil | June 18, 1893 | July 26, 1893 | First baseman | St. Louis Browns (NL) | [66] |
| Ed O'Neil | June 20, 1890 | October 12, 1890 | Pitcher | Toledo Maumees, Philadelphia Athletics (AA) | [67] |
| Fancy O'Neil | October 23, 1874 | October 23, 1874 | Right fielder | Hartford Dark Blues | [68] |
| Hugh O'Neil | August 20, 1875 | October 9, 1875 | Utility player | Brooklyn Atlantics | [69] |
| John O'Neil | April 16, 1946 | September 29, 1946 | Shortstop | Philadelphia Phillies | [70] |
| Mickey O'Neil | September 12, 1919 | June 19, 1927 | Catcher | Boston Braves, Brooklyn Robins, Washington Senators, New York Giants | [71] |
| Bill O'Neill | May 7, 1904 | October 7, 1906 | Outfielder | Boston Americans, Washington Senators, Chicago White Sox | [72] |
| Emmett O'Neill | August 3, 1943 | June 5, 1946 | Pitcher | Boston Red Sox, Chicago Cubs, Chicago White Sox | [73] |
| Fred O'Neill | May 3, 1887 | May 22, 1887 | Outfielder | New York Metropolitans | [74] |
| Harry O'Neill (P) | September 15, 1922 | May 28, 1923 | Pitcher | Philadelphia Athletics | [75] |
| Harry O'Neill (C) | July 23, 1939 | July 23, 1939 | Catcher | Philadelphia Athletics | [76] |
| Jack O'Neill | April 21, 1902 | October 3, 1906 | Catcher | St. Louis Cardinals, Chicago Cubs, Boston Beaneaters | [77] |
| Jim O'Neill | April 15, 1920 | July 29, 1923 | Shortstop | Washington Senators | [78] |
| John O'Neill | September 6, 1899 | September 5, 1902 | Catcher | New York Giants | [79] |
| Mike O'Neill | September 20, 1901 | October 6, 1907 | Pitcher | St. Louis Cardinals | [80] |
| Paul O'Neill | September 3, 1985 | October 7, 2001 | Outfielder | Cincinnati Reds, New York Yankees | [81] |
| Peaches O'Neill | April 16, 1904 | August 4, 1904 | Catcher | Cincinnati Reds | [82] |
| Steve O'Neill | September 18, 1911 | September 14, 1928 | Catcher | Cleveland Naps/Indians, Boston Red Sox, New York Yankees, St. Louis Browns | [83] |
| Tip O'Neill | May 5, 1883 | August 30, 1892 | Outfielder | New York Gothams, St. Louis Browns, Chicago Pirates, Cincinnati Reds | [84] |
| Don O'Riley | June 20, 1969 | August 1, 1970 | Pitcher | Kansas City Royals | [85] |
| O'Rourke, first name unknown | July 9, 1872 | July 9, 1872 | Pitcher | Eckford of Brooklyn | [86] |
| Charlie O'Rourke | June 16, 1959 | June 16, 1959 | Pinch hitter | St. Louis Cardinals | [87] |
| Frank O'Rourke | June 12, 1912 | July 28, 1931 | Third baseman | Boston Braves, Brooklyn Robins, Washington Senators, Boston Red Sox, Detroit Tigers, St. Louis Browns | [88] |
| Jim O'Rourke β | April 26, 1872 | September 22, 1904 | Outfielder | Middletown Mansfields, Boston Red Stockings/Red Caps, Providence Grays, Buffalo Bisons (NL), New York Giants, New York Giants (PL), Washington Senators (NL) | [89] |
| Jimmy O'Rourke | August 15, 1908 | October 8, 1908 | Utility player | New York Highlanders | [90] |
| Joe O'Rourke | April 19, 1929 | June 5, 1929 | Pinch hitter | Philadelphia Phillies | [91] |
| John O'Rourke | May 1, 1879 | September 10, 1883 | Outfielder | Boston Red Caps, New York Metropolitans | [92] |
| Mike O'Rourke | September 1, 1890 | October 15, 1890 | Pitcher | Baltimore Orioles (AA) | [93] |
| Patsy O'Rourke | April 16, 1908 | July 12, 1908 | Shortstop | St. Louis Cardinals | [94] |
| Tim O'Rourke | May 27, 1890 | August 7, 1894 | Utility player | Syracuse Stars (AA), Columbus Solons, Baltimore Orioles (NL), Louisville Colonels, St. Louis Browns (NL), Washington Senators (NL) | [95] |
| Tom O'Rourke | May 11, 1887 | August 1, 1890 | Catcher | Boston Beaneaters, New York Giants, Syracuse Stars (AA) | [96] |
| Sean O'Sullivan | June 16, 2009 | Pitcher | Los Angeles Angels of Anaheim, Kansas City Royals | [97] | |
| Dennis O'Toole | September 8, 1969 | June 23, 1973 | Pitcher | Chicago White Sox | [98] |
| Jim O'Toole | September 26, 1958 | July 22, 1967 | Pitcher | Cincinnati Redlegs/Reds, Chicago White Sox | [99] |
| Marty O'Toole | September 21, 1908 | October 6, 1914 | Pitcher | Cincinnati Reds, Pittsburgh Pirates, New York Giants | [100] |
| Rebel Oakes | April 14, 1909 | October 3, 1915 | Outfielder | Cincinnati Reds, St. Louis Cardinals, Pittsburgh Rebels | [101] |
| Prince Oana | April 22, 1934 | September 18, 1945 | Pitcher | Philadelphia Phillies, Detroit Tigers | [102] |
| Johnny Oates | September 17, 1970 | May 24, 1981 | Catcher | Baltimore Orioles, Atlanta Braves, Philadelphia Phillies, Los Angeles Dodgers, New York Yankees | [103] |
| Sherman Obando | April 10, 1993 | July 21, 1997 | Outfielder | Baltimore Orioles, Montreal Expos | [104] |
| Henry Oberbeck | May 7, 1883 | October 18, 1884 | Outfielder | Pittsburgh Alleghenys, St. Louis Browns (AA), Baltimore Monumentals, Kansas City Cowboys (UA) | [105] |
| Ken Oberkfell | August 22, 1977 | October 4, 1992 | Third baseman | St. Louis Cardinals, Atlanta Braves, Pittsburgh Pirates, San Francisco Giants, Houston Astros, California Angels | [106] |
| Doc Oberlander | May 16, 1888 | June 2, 1888 | Pitcher | Cleveland Blues (AA) | [107] |
| Frank Oberlin | September 20, 1906 | June 28, 1910 | Pitcher | Boston Red Sox, Washington Senators | [108] |
| Wes Obermueller | September 20, 2002 | July 13, 2007 | Pitcher | Kansas City Royals, Milwaukee Brewers, Florida Marlins | [109] |
| Jim Obradovich | September 12, 1978 | September 29, 1978 | First baseman | Houston Astros | [110] |
| Alex Ochoa | September 18, 1995 | September 29, 2002 | Outfielder | New York Mets, Minnesota Twins, Milwaukee Brewers, Cincinnati Reds, Colorado Rockies, Anaheim Angels | [111] |
| Iván Ochoa | July 12, 2008 | Shortstop | San Francisco Giants | [112] | |
| Whitey Ock | September 29, 1935 | September 29, 1935 | Catcher | Brooklyn Dodgers | [113] |
| Walter Ockey | May 3, 1944 | May 20, 1944 | Pitcher | New York Giants | [114] |
| Ted Odenwald | April 13, 1921 | April 21, 1922 | Pitcher | Cleveland Indians | [115] |
| Blue Moon Odom | September 5, 1964 | August 17, 1976 | Pitcher | Kansas City/Oakland Athletics, Cleveland Indians, Atlanta Braves, Chicago White Sox | [116] |
| Dave Odom | May 31, 1943 | September 13, 1943 | Pitcher | Boston Braves | [117] |
| Heinie Odom | April 22, 1925 | April 22, 1925 | Third baseman | New York Yankees | [118] |
| Fred Odwell | April 16, 1904 | September 12, 1907 | Outfielder | Cincinnati Reds | [119] |
| Bryan Oelkers | April 9, 1983 | October 3, 1986 | Pitcher | Minnesota Twins, Cleveland Indians | [120] |
| Trent Oeltjen | August 6, 2009 | Outfielder | Arizona Diamondbacks, Los Angeles Dodgers | [121] | |
| Chuck Oertel | September 1, 1958 | September 26, 1958 | Outfielder | Baltimore Orioles | [122] |
| Joe Oeschger | April 21, 1914 | September 6, 1925 | Pitcher | Philadelphia Phillies, New York Giants, Boston Braves, Philadelphia Phillies, Brooklyn Robins | [123] |
| Ron Oester | September 10, 1978 | October 3, 1990 | Second baseman | Cincinnati Reds | [124] |
| José Offerman | August 19, 1990 | October 2, 2005 | Utility infielder | Los Angeles Dodgers, Kansas City Royals, Boston Red Sox, Seattle Mariners, Minnesota Twins, Philadelphia Phillies, New York Mets | [125] |
| Rowland Office | August 5, 1972 | April 20, 1983 | Outfielder | Atlanta Braves, Montreal Expos, New York Yankees | [126] |
| Alexi Ogando | June 15, 2010 | Pitcher | Texas Rangers | [127] | |
| Curly Ogden | July 18, 1922 | July 21, 1926 | Pitcher | Philadelphia Athletics, Washington Senators | [128] |
| Jack Ogden | June 22, 1918 | September 9, 1932 | Pitcher | New York Giants, St. Louis Browns, Cincinnati Reds | [129] |
| Chad Ogea | May 3, 1994 | October 2, 1999 | Pitcher | Cleveland Indians, Philadelphia Phillies | [130] |
| Jim Oglesby | April 14, 1936 | April 17, 1936 | First baseman | Philadelphia Athletics | [131] |
| Ben Oglivie | September 4, 1971 | October 5, 1986 | Outfielder | Boston Red Sox, Detroit Tigers, Milwaukee Brewers | [132] |
| Bruce Ogrodowski | April 14, 1936 | October 3, 1937 | Catcher | St. Louis Cardinals | [133] |
| Joe Ogrodowski | April 27, 1925 | April 27, 1925 | Pitcher | Boston Braves | [134] |
| Tomo Ohka | July 19, 1999 | Pitcher | Boston Red Sox, Montreal Expos, Washington Nationals, Milwaukee Brewers, Toronto Blue Jays, Cleveland Indians | [135] | |
| Joe Ohl | July 29, 1909 | August 5, 1909 | Pitcher | Washington Senators | [136] |
| Ross Ohlendorf | September 11, 2007 | Pitcher | New York Yankees, Pittsburgh Pirates | [137] | |
| Will Ohman | September 19, 2000 | Pitcher | Chicago Cubs, Atlanta Braves, Los Angeles Dodgers, Baltimore Orioles, Florida Marlins, Chicago White Sox | [138] | |
| Kevin Ohme | April 14, 2003 | April 15, 2003 | Pitcher | St. Louis Cardinals | [139] |
| Kirt Ojala | August 18, 1997 | May 4, 1999 | Pitcher | Florida Marlins | [140] |
| Augie Ojeda | June 4, 2000 | Utility infielder | Chicago Cubs, Minnesota Twins, Arizona Diamondbacks | [141] | |
| Bob Ojeda | July 13, 1980 | April 22, 1994 | Pitcher | Boston Red Sox, New York Mets, Los Angeles Dodgers, Cleveland Indians, New York Yankees | [142] |
| Miguel Ojeda | May 17, 2003 | October 1, 2006 | Catcher | San Diego Padres, Seattle Mariners, Colorado Rockies, Texas Rangers | [143] |
| Hideki Okajima | April 2, 2007 | Pitcher | Boston Red Sox | [144] | |
| Frank Okrie | April 20, 1920 | August 4, 1920 | Pitcher | Detroit Tigers | [145] |
| Len Okrie | June 16, 1948 | April 16, 1952 | Catcher | Washington Senators, Boston Red Sox | [146] |
| Jim Olander | September 20, 1991 | October 5, 1991 | Outfielder | Milwaukee Brewers | [147] |
| Patrick O'Loughlin | May 9, 1883 | May 9, 1883 | Outfielder | Baltimore Orioles (AA) | [148] |
| Dave Oldfield | June 28, 1883 | October 11, 1886 | Catcher | Baltimore Orioles (AA), Brooklyn Grays, Washington Nationals (1886–1889) | [149] |
| John Oldham | September 2, 1956 | September 2, 1956 | Pinch runner | Cincinnati Redlegs | [150] |
| Red Oldham | August 19, 1914 | July 8, 1926 | Pitcher | Detroit Tigers, Pittsburgh Pirates | [151] |
| Bob Oldis | April 28, 1953 | September 29, 1963 | Catcher | Washington Senators, Pittsburgh Pirates, Philadelphia Phillies | [152] |
| Rube Oldring | October 2, 1905 | August 30, 1918 | Outfielder | New York Highlanders/Yankees, Philadelphia Athletics | [153] |
| John Olerud | September 3, 1989 | October 2, 2005 | First baseman | Toronto Blue Jays, New York Mets, Seattle Mariners, New York Yankees, Boston Red Sox | [154] |
| Frank Olin | July 4, 1884 | June 10, 1885 | Outfielder | Washington Nationals (AA), Washington Nationals (UA), Toledo Blue Stockings, Detroit Wolverines | [155] |
| Steve Olin | July 29, 1989 | October 4, 1992 | Pitcher | Cleveland Indians | [156] |
| José Oliva | July 1, 1994 | October 1, 1995 | Third baseman | Atlanta Braves, St. Louis Cardinals | [157] |
| Tony Oliva | September 9, 1962 | September 29, 1976 | Outfielder | Minnesota Twins | [158] |
| Ed Olivares | September 16, 1960 | September 26, 1961 | Outfielder | St. Louis Cardinals | [159] |
| Omar Olivares | August 18, 1990 | September 28, 2001 | Pitcher | St. Louis Cardinals, Colorado Rockies, Philadelphia Phillies, Detroit Tigers, Seattle Mariners, Anaheim Angels, Oakland Athletics, Pirates | [160] |
| Al Oliver | September 23, 1968 | October 5, 1985 | Outfielder | Pittsburgh Pirates, Texas Rangers, Montreal Expos, San Francisco Giants, Philadelphia Phillies, Los Angeles Dodgers, Toronto Blue Jays | [161] |
| Andrew Oliver | June 25, 2010 | Pitcher | Detroit Tigers | [162] | |
| Bob Oliver | September 10, 1965 | July 3, 1975 | First baseman | Pittsburgh Pirates, Kansas City Royals, California Angels, Baltimore Orioles, New York Yankees | [163] |
| Darren Oliver | September 1, 1993 | Pitcher | Texas Rangers, St. Louis Cardinals, Boston Red Sox, Colorado Rockies, Florida Marlins, Houston Astros, New York Mets, Los Angeles Angels of Anaheim | [164] | |
| Dave Oliver | September 25, 1977 | October 2, 1977 | Second baseman | Cleveland Indians | [165] |
| Gene Oliver | June 6, 1959 | August 24, 1969 | Utility player | St. Louis Cardinals, Milwaukee/Atlanta Braves, Philadelphia Phillies, Boston Red Sox, Chicago Cubs | [166] |
| Joe Oliver | July 15, 1989 | October 6, 2001 | Catcher | Cincinnati Reds, Milwaukee Brewers, Detroit Tigers, Seattle Mariners, New York Yankees, Boston Red Sox | [167] |
| Nate Oliver | April 9, 1963 | September 27, 1969 | Second baseman | Los Angeles Dodgers, San Francisco Giants, New York Yankees, Chicago Cubs | [168] |
| Tom Oliver | April 14, 1930 | September 23, 1933 | Outfielder | Boston Red Sox | [169] |
| Francisco Oliveras | May 3, 1989 | October 3, 1992 | Pitcher | Minnesota Twins, San Francisco Giants | [170] |
| Lester Oliveros | July 1, 2011 | Pitcher | Detroit Tigers, Minnesota Twins | [171] | |
| Chi-Chi Olivo | June 5, 1961 | October 1, 1966 | Pitcher | Milwaukee/Atlanta Braves | [172] |
| Diomedes Olivo | September 5, 1960 | June 12, 1963 | Pitcher | Pittsburgh Pirates, St. Louis Cardinals | [173] |
| Miguel Olivo | September 15, 2002 | Catcher | Chicago White Sox, Seattle Mariners, San Diego Padres, Florida Marlins, Kansas City Royals, Colorado Rockies, Seattle Mariners | [174] | |
| Jim Ollom | September 3, 1966 | September 15, 1967 | Pitcher | Minnesota Twins | [175] |
| Ray Olmedo | May 25, 2003 | Shortstop | Cincinnati Reds, Toronto Blue Jays | [176] | |
| Luis Olmo | July 23, 1943 | June 6, 1951 | Outfielder | Brooklyn Dodgers, Boston Braves | [177] |
| Fred Olmstead | July 2, 1908 | September 4, 1911 | Pitcher | Chicago White Sox | [178] |
| Al Olmsted | September 12, 1980 | October 3, 1980 | Pitcher | St. Louis Cardinals | [179] |
| Hank Olmsted | July 15, 1905 | July 26, 1905 | Pitcher | Boston Americans | [180] |
| Barney Olsen | April 17, 1941 | September 28, 1941 | Outfielder | Chicago Cubs | [181] |
| Kevin Olsen | September 7, 2001 | September 27, 2003 | Pitcher | Florida Marlins | [182] |
| Ole Olsen | April 12, 1922 | September 24, 1923 | Pitcher | Detroit Tigers | [183] |
| Scott Olsen | June 25, 2005 | Pitcher | Florida Marlins, Washington Nationals | [184] | |
| Vern Olsen | September 8, 1939 | September 13, 1946 | Pitcher | Chicago Cubs | [185] |
| Garrett Olson | July 4, 2007 | Pitcher | Baltimore Orioles, Seattle Mariners, Pittsburgh Pirates | [186] | |
| Greg Olson | June 27, 1989 | September 30, 1993 | Catcher | Minnesota Twins, Atlanta Braves | [187] |
| Gregg Olson | September 2, 1988 | June 22, 2001 | Pitcher | Baltimore Orioles, Atlanta Braves, Cleveland Indians, Kansas City Royals, Detroit Tigers, Houston Astros, Minnesota Twins, Arizona Diamondbacks, Los Angeles Dodgers | [188] |
| Ivy Olson | April 12, 1911 | July 21, 1924 | Shortstop | Cleveland Naps, Cincinnati Reds, Brooklyn Robins | [189] |
| Karl Olson | June 30, 1951 | June 10, 1957 | Outfielder | Boston Red Sox, Washington Senators, Detroit Tigers | [190] |
| Marv Olson | September 13, 1931 | April 30, 1933 | Second baseman | Boston Red Sox | [191] |
| Ted Olson | June 21, 1936 | September 13, 1938 | Pitcher | Boston Red Sox | [192] |
| Tim Olson | May 30, 2004 | June 19, 2005 | Utility infielder | Arizona Diamondbacks, Colorado Rockies | [193] |
| Ed Olwine | June 2, 1986 | October 2, 1988 | Pitcher | Atlanta Braves | [194] |
| Logan Ondrusek | April 5, 2010 | Pitcher | Cincinnati Reds | [195] | |
| Ralph Onis | April 27, 1935 | April 27, 1935 | Catcher | Brooklyn Dodgers | [196] |
| Eddie Onslow | August 7, 1912 | September 14, 1927 | First baseman | Detroit Tigers, Cleveland Indians, Washington Senators | [197] |
| Jack Onslow | May 2, 1912 | October 3, 1917 | Catcher | Detroit Tigers, New York Giants | [198] |
| Steve Ontiveros (IF) | August 5, 1973 | June 21, 1980 | Third baseman | San Francisco Giants, Chicago Cubs | [199] |
| Steve Ontiveros (P) | June 14, 1985 | October 1, 2000 | Pitcher | Oakland Athletics, Philadelphia Phillies, Seattle Mariners, Boston Red Sox | [200] |
| José Oquendo | May 2, 1983 | September 29, 1995 | Second baseman | New York Mets, St. Louis Cardinals | [201] |
| Mike Oquist | August 14, 1993 | September 21, 1999 | Pitcher | Baltimore Orioles, San Diego Padres, Oakland Athletics | [202] |
| Tom Oran | May 4, 1875 | July 4, 1875 | Outfielder | St. Louis Red Stockings | [203] |
| Ernie Oravetz | April 11, 1955 | September 30, 1956 | Outfielder | Washington Senators | [204] |
| Luis Ordaz | September 3, 1997 | April 3, 2006 | Shortstop | St. Louis Cardinals, Kansas City Royals, Tampa Bay Devil Rays | [205] |
| Tony Ordeñana | October 3, 1943 | October 3, 1943 | Shortstop | Pittsburgh Pirates | [206] |
| Magglio Ordóñez | August 29, 1997 | Outfielder | Chicago White Sox, Detroit Tigers | [207] | |
| Rey Ordóñez | April 1, 1996 | July 17, 2004 | Shortstop | New York Mets, Tampa Bay Devil Rays, Chicago Cubs | [208] |
| Joe Orengo | April 18, 1939 | September 25, 1945 | Utility infielder | St. Louis Cardinals, New York Giants, Brooklyn Dodgers, Detroit Tigers, Chicago White Sox | [209] |
| Kevin Orie | April 1, 1997 | September 26, 2002 | Third baseman | Chicago Cubs, Florida Marlins | [210] |
| George Orme | September 14, 1920 | September 17, 1920 | Outfielder | Boston Red Sox | [211] |
| Jess Orndorff | April 18, 1907 | April 24, 1907 | Catcher | Boston Doves | [212] |
| Eddie Oropesa | April 2, 2001 | May 20, 2004 | Pitcher | Philadelphia Phillies, Arizona Diamondbacks, San Diego Padres | [213] |
| Jesse Orosco | April 5, 1979 | September 27, 2003 | Pitcher | New York Mets, Los Angeles Dodgers, Cleveland Indians, Milwaukee Brewers, Baltimore Orioles, St. Louis Cardinals, San Diego Padres, New York Yankees, Minnesota Twins | [214] |
| Billy Orr | May 3, 1913 | May 22, 1914 | Shortstop | Philadelphia Athletics | [215] |
| Dave Orr | May 17, 1883 | October 2, 1890 | First baseman | New York Metropolitans, New York Gothams, Brooklyn Bridegrooms, Columbus Solons, Brooklyn Ward's Wonders | [216] |
| Pete Orr | April 5, 2005 | Utility infielder | Atlanta Braves, Washington Nationals, Philadelphia Phillies | [217] | |
| Joe Orrell | August 12, 1943 | August 6, 1945 | Pitcher | Detroit Tigers | [218] |
| Ernie Orsatti | September 4, 1927 | September 28, 1935 | Outfielder | St. Louis Cardinals | [219] |
| John Orsino | July 14, 1961 | September 10, 1967 | Catcher | San Francisco Giants, Baltimore Orioles, Washington Senators (1961–1971) | [220] |
| Joe Orsulak | September 1, 1983 | September 25, 1997 | Outfielder | Pittsburgh Pirates, Baltimore Orioles, New York Mets, Florida Marlins, Montreal Expos | [221] |
| Jorge Orta | April 15, 1972 | June 10, 1987 | Second baseman | Chicago White Sox, Cleveland Indians, Los Angeles Dodgers, Toronto Blue Jays, Kansas City Royals | [222] |
| Anthony Ortega | April 25, 2009 | Pitcher | Los Angeles Angels of Anaheim | [223] | |
| Bill Ortega | September 7, 2001 | September 28, 2001 | Pinch hitter | St. Louis Cardinals | [224] |
| Phil Ortega | September 10, 1960 | May 4, 1969 | Pitcher | Los Angeles Dodgers, Washington Senators (1961–1971), California Angels | [225] |
| Frank Ortenzio | September 9, 1973 | September 30, 1973 | First baseman | Kansas City Royals | [226] |
| Al Orth | August 15, 1895 | September 20, 1909 | Pitcher | Philadelphia Phillies, Washington Senators, New York Highlanders | [227] |
| Baby Ortiz | September 23, 1944 | September 27, 1944 | Pitcher | Washington Senators | [228] |
| David Ortiz | September 2, 1997 | Designated hitter | Minnesota Twins, Boston Red Sox | [229] | |
| Héctor Ortiz | September 14, 1998 | May 15, 2002 | Catcher | Kansas City Royals, Texas Rangers | [230] |
| Javier Ortiz | June 15, 1990 | October 6, 1991 | Outfielder | Houston Astros | [231] |
| José Ortiz (OF) | September 4, 1969 | June 16, 1971 | Outfielder | Chicago White Sox, Chicago Cubs | [232] |
| José Ortiz (2B) | September 15, 2000 | September 27, 2002 | Second baseman | Oakland Athletics, Colorado Rockies | [233] |
| Junior Ortiz | September 20, 1982 | August 8, 1994 | Catcher | Pittsburgh Pirates, New York Mets, Minnesota Twins, Cleveland Indians, Texas Rangers | [234] |
| Luis Ortiz | August 31, 1993 | September 28, 1996 | Third baseman | Boston Red Sox, Texas Rangers | [235] |
| Ramón Ortiz | August 19, 1999 | Pitcher | Anaheim Angels, Cincinnati Reds, Washington Nationals, Minnesota Twins, Colorado Rockies, Los Angeles Dodgers, Chicago Cubs | [236] | |
| Roberto Ortiz | September 6, 1941 | September 2, 1950 | Outfielder | Washington Senators, Philadelphia Athletics | [237] |
| Russ Ortiz | April 2, 1998 | Pitcher | San Francisco Giants, Atlanta Braves, Arizona Diamondbacks, Baltimore Orioles, Houston Astros, Los Angeles Dodgers | [238] | |
| Daniel Ortmeier | September 5, 2005 | Outfielder | San Francisco Giants | [239] | |
| John Orton | August 20, 1989 | July 4, 1993 | Catcher | California Angels | [240] |
| Chad Orvella | May 31, 2005 | Pitcher | Tampa Bay Devil Rays | [241] | |
| Ossie Orwoll | April 13, 1928 | August 21, 1929 | Utility player | Philadelphia Athletics | [242] |
| Bob Osborn | September 16, 1925 | September 24, 1931 | Pitcher | Chicago Cubs, Pittsburgh Pirates | [243] |
| Fred Osborn | June 8, 1907 | July 24, 1909 | Outfielder | Philadelphia Phillies | [244] |
| Ozzie Osborn | April 26, 1975 | September 23, 1975 | Pitcher | Chicago White Sox | [245] |
| Bobo Osborne | June 27, 1957 | September 24, 1963 | First baseman | Detroit Tigers, Washington Senators (1961–1971) | [246] |
| Donovan Osborne | April 9, 1992 | May 15, 2004 | Pitcher | St. Louis Cardinals, Chicago Cubs, New York Yankees | [247] |
| Fred Osborne | July 14, 1890 | September 1, 1890 | Outfielder | Pittsburgh Alleghenys | [248] |
| Tiny Osborne | April 15, 1922 | September 28, 1925 | Pitcher | Chicago Cubs, Brooklyn Robins | [249] |
| Wayne Osborne | April 18, 1935 | May 6, 1936 | Pitcher | Pittsburgh Pirates, Boston Bees | [250] |
| Pat Osburn | April 13, 1974 | September 22, 1975 | Pitcher | Cincinnati Reds, Milwaukee Brewers | [251] |
| Charlie Osgood | June 18, 1944 | June 18, 1944 | Pitcher | Brooklyn Dodgers | [252] |
| Keith Osik | April 5, 1996 | October 1, 2005 | Catcher | Pittsburgh Pirates, Milwaukee Brewers, Baltimore Orioles, Washington Nationals | [253] |
| Dan Osinski | April 11, 1962 | April 16, 1970 | Pitcher | Los Angeles Angels, Milwaukee Braves, Boston Red Sox, Chicago White Sox, Houston Astros | [254] |
| Franquelis Osoria | June 7, 2005 | July 30, 2008 | Pitcher | Los Angeles Dodgers, Pittsburgh Pirates | [255] |
| Harry Ostdiek | September 10, 1904 | October 7, 1908 | Catcher | Cleveland Naps, Boston Red Sox | [256] |
| Champ Osteen | September 18, 1903 | May 3, 1909 | Shortstop | Washington Senators, New York Yankees, St. Louis Cardinals | [257] |
| Claude Osteen | July 6, 1957 | September 27, 1975 | Pitcher | Cincinnati Redlegs/Reds, Washington Senators (1961–1971), Los Angeles Dodgers, Houston Astros, St. Louis Cardinals, Chicago White Sox | [258] |
| Darrell Osteen | September 2, 1965 | July 19, 1970 | Pitcher | Cincinnati Reds, Oakland Athletics | [259] |
| Fred Ostendorf | July 16, 1914 | July 16, 1914 | Pitcher | Indianapolis Hoosiers (FL) | [260] |
| Bill Oster | August 23, 1954 | September 20, 1954 | Pitcher | Philadelphia Athletics | [261] |
| Red Ostergard | June 14, 1921 | August 17, 1921 | Pinch hitter | Chicago White Sox | [262] |
| Charlie Osterhout | June 23, 1879 | September 6, 1879 | Catcher/Outfielder | Syracuse Stars (NL) | [263] |
| Fritz Ostermueller | April 21, 1934 | September 30, 1948 | Pitcher | Boston Red Sox, St. Louis Browns, Brooklyn Dodgers, Pittsburgh Pirates | [264] |
| Jimmy Osting | May 2, 2001 | August 27, 2002 | Pitcher | San Diego Padres, Milwaukee Brewers | [265] |
| Brian Ostrosser | August 5, 1973 | August 13, 1973 | Shortstop | New York Mets | [266] |
| Joe Ostrowski | July 18, 1948 | August 20, 1952 | Pitcher | St. Louis Browns, New York Yankees | [267] |
| Johnny Ostrowski | September 24, 1943 | October 1, 1950 | Outfielder | Chicago Cubs, Boston Red Sox, Chicago White Sox, Washington Senators | [268] |
| Al Osuna | September 2, 1990 | September 27, 1996 | Pitcher | Houston Astros, Los Angeles Dodgers, San Diego Padres | [269] |
| Antonio Osuna | April 25, 1995 | April 10, 2005 | Pitcher | Los Angeles Dodgers, Chicago White Sox, New York Yankees, San Diego Padres, Washington Nationals | [270] |
| Roy Oswalt | May 6, 2001 | Pitcher | Houston Astros, Philadelphia Phillies | [271] | |
| Willis Otáñez | August 25, 1998 | October 3, 1999 | Third baseman | Baltimore Orioles, Toronto Blue Jays | [272] |
| Reggie Otero | September 2, 1945 | September 29, 1945 | First baseman | Chicago Cubs | [273] |
| Ricky Otero | April 26, 1995 | August 17, 1997 | Outfielder | New York Mets, Philadelphia Phillies | [274] |
| Bill Otey | September 27, 1907 | June 24, 1911 | Pitcher | Pittsburgh Pirates, Washington Senators | [275] |
| Amos Otis | September 6, 1967 | August 5, 1984 | Outfielder | New York Mets, Kansas City Royals, Pittsburgh Pirates | [276] |
| Bill Otis | July 4, 1912 | July 6, 1912 | Outfielder | New York Highlanders | [277] |
| Harry Otis | September 5, 1909 | September 29, 1909 | Pitcher | Cleveland Naps | [278] |
| Akinori Otsuka | April 6, 2004 | July 1, 2007 | Pitcher | San Diego Padres, Texas Rangers | [279] |
| Billy Ott | September 4, 1962 | July 14, 1964 | Outfielder | Chicago Cubs | [280] |
| Ed Ott | June 10, 1974 | October 2, 1981 | Catcher | Pittsburgh Pirates, California Angels | [281] |
| Mel Ott β | April 27, 1926 | July 11, 1947 | Outfielder | New York Giants | [282] |
| Adam Ottavino | May 29, 2010 | Pitcher | St. Louis Cardinals | [283] | |
| Jim Otten | July 31, 1974 | September 30, 1981 | Pitcher | Chicago White Sox, St. Louis Cardinals | [284] |
| John Otten | July 5, 1895 | September 28, 1895 | Catcher | St. Louis Browns (NL) | [285] |
| Billy Otterson | September 4, 1887 | October 10, 1887 | Shortstop | Brooklyn Grays | [286] |
| Dave Otto | September 8, 1987 | August 10, 1994 | Pitcher | Oakland Athletics, Cleveland Indians, Pittsburgh Pirates, Chicago Cubs | [287] |
| Phil Ouellette | September 10, 1986 | October 3, 1986 | Catcher | San Francisco Giants | [288] |
| Johnny Oulliber | July 25, 1933 | October 1, 1933 | Outfielder | Cleveland Indians | [289] |
| Chink Outen | April 16, 1933 | October 1, 1933 | Catcher | Brooklyn Dodgers | [290] |
| Jimmy Outlaw | April 20, 1937 | May 8, 1949 | Outfielder | Cincinnati Reds, Boston Bees, Detroit Tigers | [291] |
| Josh Outman | September 2, 2008 | Pitcher | Oakland Athletics | [292] | |
| Orval Overall | April 16, 1905 | July 29, 1913 | Pitcher | Cincinnati Reds, Chicago Cubs | [293] |
| Lyle Overbay | September 19, 2001 | First baseman | Arizona Diamondbacks, Milwaukee Brewers, Toronto Blue Jays, Pittsburgh Pirates | [294] | |
| Stubby Overmire | April 25, 1943 | August 3, 1952 | Pitcher | Detroit Tigers, St. Louis Browns, New York Yankees | [295] |
| Mike Overy | August 14, 1976 | September 9, 1976 | Pitcher | California Angels | [296] |
| Ernie Ovitz | June 22, 1911 | June 22, 1911 | Pitcher | Chicago Cubs | [297] |
| Bob Owchinko | September 25, 1976 | October 1, 1986 | Pitcher | San Diego Padres, Cleveland Indians, Oakland Athletics, Pittsburgh Pirates, Cincinnati Reds, Montreal Expos | [298] |
| Dave Owen | September 6, 1983 | October 2, 1988 | Shortstop | Chicago Cubs, Kansas City Royals | [299] |
| Frank Owen | April 29, 1901 | May 12, 1909 | Pitcher | Detroit Tigers, Chicago White Sox | [300] |
| Larry Owen | August 14, 1981 | September 25, 1988 | Catcher | Atlanta Braves, Kansas City Royals | [301] |
| Marv Owen | April 16, 1931 | August 2, 1940 | Third baseman | Detroit Tigers, Chicago White Sox, Boston Red Sox | [302] |
| Mickey Owen | May 2, 1937 | September 11, 1954 | Catcher | St. Louis Cardinals, Brooklyn Dodgers, Chicago Cubs, Boston Red Sox | [303] |
| Spike Owen | June 25, 1983 | October 2, 1995 | Shortstop | Seattle Mariners, Boston Red Sox, Montreal Expos, New York Yankees, California Angels | [304] |
| Eric Owens | June 6, 1995 | September 27, 2003 | Outfielder | Cincinnati Reds, Milwaukee Brewers, San Diego Padres, Florida Marlins, Anaheim Angels | [305] |
| Henry Owens | July 7, 2006 | Pitcher | New York Mets, Florida Marlins | [306] | |
| Jack Owens | September 21, 1935 | September 22, 1935 | Catcher | Philadelphia Athletics | [307] |
| Jayhawk Owens | June 6, 1993 | September 28, 1996 | Catcher | Colorado Rockies | [308] |
| Jerry Owens | September 11, 2006 | Outfielder | Chicago White Sox | [309] | |
| Jim Owens | April 19, 1955 | June 20, 1967 | Pitcher | Philadelphia Phillies, Cincinnati Reds, Houston Colt .45s/Astros | [310] |
| Red Owens | July 28, 1899 | May 31, 1905 | Second baseman | Philadelphia Phillies, Brooklyn Superbas | [311] |
| Yip Owens | September 11, 1905 | October 3, 1915 | Catcher | Boston Americans, Chicago White Sox, Brooklyn Tip-Tops, Baltimore Terrapins | [312] |
| Micah Owings | April 6, 2007 | Pitcher | Arizona Diamondbacks, Cincinnati Reds | [313] | |
| Rick Ownbey | August 17, 1982 | July 3, 1986 | Pitcher | New York Mets, St. Louis Cardinals | [314] |
| Henry Oxley | July 30, 1884 | October 10, 1884 | Catcher | New York Gothams, New York Metropolitans | [315] |
| Chris Oxspring | September 2, 2005 | September 17, 2005 | Pitcher | San Diego Padres | [316] |
| Andy Oyler | May 8, 1902 | July 21, 1902 | Third baseman | Baltimore Orioles (1901–02) | [317] |
| Ray Oyler | April 18, 1965 | October 1, 1970 | Shortstop | Detroit Tigers, Seattle Pilots, California Angels | [318] |
| Doc Ozmer | May 11, 1923 | May 11, 1923 | Pitcher | Philadelphia Athletics | [319] |
| Pablo Ozuna | April 23, 2000 | Utility player | Florida Marlins, Colorado Rockies, Chicago White Sox, Los Angeles Dodgers | [320] |
Below are select minor league players and the rosters of the minor league affiliates of the Texas Rangers: