In baseball, the umpire is the person charged with officiating the game, including beginning and ending the game, enforcing the rules of the game and the grounds, making judgment calls on plays, and handling the disciplinary actions. The term is often shortened to the colloquial form ump. They are also sometimes addressed as blue at lower levels due to the common color of the uniform worn by umpires. In professional baseball, the term blue is seldom used by players or managers, who instead call the umpire by name. Although games were often officiated by a sole umpire in the formative years of the sport, since the turn of the 20th century, officiating has been commonly divided among several umpires, who form the umpiring crew. The position is analogous to that of a referee in many other sports.
Julius Edward "Chuck" Meriwether was a Major League Baseball (MLB) umpire. After working in the American League (AL) from 1988 to 1999, he umpired in both leagues from 2000 to 2009. Meriwether originally wore number 32, but in 2004 switched to number 14.
Donald Anton Denkinger was an American umpire in Major League Baseball (MLB) who worked in the American League (AL) from 1969 to 1998. Denkinger wore uniform number 11, when the AL adopted uniform numbers in 1980. He is best remembered for an incorrect safe call he made at first base in Game 6 of the 1985 World Series, which came to be known as The Call.
Lee Howard "Big Lee" Weyer was an American umpire in Major League Baseball who worked in the National League from 1961 until his death. In a 1987 Sports Illustrated poll of National League catchers, Weyer was rated the best at calling balls and strikes. He was the home plate umpire on September 11, 1985, in Cincinnati's Riverfront Stadium when Pete Rose collected his 4,192nd hit to break Ty Cobb's career record, and was the third base umpire in the April 8, 1974 game in which Hank Aaron broke Babe Ruth's record of 714 career home runs.
Larry Sanders McCoy is a former umpire in Major League Baseball who worked in the American League from 1970 to 1999.
Joseph Norbert Brinkman is an American former umpire in Major League Baseball (MLB) who worked in the American League (AL) from 1972 to 1999 and throughout both major leagues from 2000 until his retirement during the 2006 season.
Stephen Michael Palermo was an umpire in Major League Baseball who worked in the American League from 1977 to 1991. His field career ended when he was shot in the back following his decision to intervene and apprehend the assailants in an altercation outside Campisi's, a Dallas Italian restaurant. He wore uniform number 14 when the American League began using uniform numbers for its umpires in 1980, and the number was never reassigned to another AL umpire until after the AL and NL umpire staffs were unified by MLB in 2000.
Edwin Durwood Merrill was an American umpire in Major League Baseball (MLB) who worked in the American League for 23 seasons (1977–1999).
Gerald Joseph Crawford is an American former umpire in Major League Baseball. He first umpired in the National League from 1977 to 1999, then worked in both major leagues from 2000 to 2010.
Lazaro Antonio Díaz Sr. is an American umpire in Major League Baseball wearing number 63, a reference to his year of birth. He joined the American League's full-time staff in 1999, and has worked throughout both major leagues since 2000. Díaz was promoted to crew chief for the 2022 season, becoming the second full time Latino crew chief, after Alfonso Marquez.
Gregory John Kosc is a former umpire in Major League Baseball who worked in the American League from 1976 to 1999. He officiated in the World Series in 1987 and 1997, and in the All-Star Game in 1981 and 1992. He also worked the American League Championship Series in 1979, 1988 and 1993, and the American League Division Series in 1996 and 1997. Kosc wore uniform number 18 when the American League umpires adopted them in 1980.
Michael John Winters is an American former umpire in Major League Baseball who has worked in the National League from 1988 to 1999 and throughout both major leagues from 2000 to 2019, wearing number 33. For the 2011 season, Winters was named a crew chief following the retirements of Jerry Crawford, Mike Reilly, and Chuck Meriwether.
Jeffrey William Kellogg is a retired Major League Baseball umpire who worked in the National League from 1991 to 1999 and throughout both major leagues from 2000 to 2019. He wore uniform number 8, formerly worn in the NL by Hall of Fame umpire Doug Harvey from 1962 to 1992.
John Andrew "Rocky" Roe is a former umpire in Major League Baseball who worked in the American League from 1979 to 1999 and in both leagues in 2000 and 2001. He officiated in the 1990 and 1999 World Series, as well as the 1984 and 1994 All-Star Games. He also worked three American League Championship Series and four Division Series. Roe wore uniform number 27 throughout his career.
Louis John DiMuro was an American umpire in Major League Baseball who worked in the American League from 1963 until his death.
Martin John Springstead was an American umpire in Major League Baseball who worked in the American League from 1966 to 1985 and had since worked as an umpire supervisor. He was the youngest umpire ever to serve as crew chief in the World Series, heading the staff for the 1973 Series at the age of 36 years and 3 months.
Jerome August Neudecker was an American Major League Baseball umpire who worked in the American League from 1966 to 1985. He wore number 6 when the league adopted uniform numbers in 1980.
William Edward John Deegan is a former Major League Baseball umpire who worked in the American League from 1971 to 1980. Deegan wore uniform number 17 when the American League adopted them for its umpires in 1980, later worn by John Hirschbeck.
James Patrick Hoye is an American umpire in Major League Baseball. He wears number 92. Hoye worked as an MLB reserve umpire from 2003 to 2009 for both the American and National Leagues. He was hired to the full-time Major League staff prior to the 2010 season. Hoye has worked two All-Star Games, two World Series, three League Championship Series, four Division Series, and five Wild Card Games/Series. He was promoted to crew chief in 2023.
Alan Marshall Clark is an American former professional baseball umpire who worked in the American League from 1976 to 1999, and throughout both Major Leagues in 2000 and 2001. He was fired for misuse of a credit card issued for professional expenses. Three years later, pled guilty to mail fraud for his involvement in a collectibles-selling scheme.
