William Joseph Klem, known as "the Old Arbitrator", was an American baseball umpire who worked in Major League Baseball from 1905 to 1941, spending his entire career in the National League (NL). He worked 18 World Series, which is a major league record. Klem was posthumously inducted into the Baseball Hall of Fame in 1953.
Thomas Henry Connolly was an English-American umpire in Major League Baseball. He officiated in the National League from 1898 to 1900, followed by 31 years of service in the American League from 1901 to 1931. In over half a century as an American League umpire and supervisor, he established the high standards for which the circuit's arbiters became known, and solidified the reputation for integrity of umpires in the major leagues.
Robert Allan Davidson is a former umpire in Major League Baseball (MLB). Nicknamed "Balkin' Bob" and "Balk-a-Day Bob" for his tendency to liberally invoke baseball's balk rule, Davidson was an umpire on the National League (NL) staff from 1982 to 1999, and he was on the combined MLB umpiring staff from 2005 to 2016. He worked one World Series (1992) and several other postseason series.
Edward George Barrett is an American retired Major League Baseball umpire. He joined the American League's staff in 1994, and worked throughout both major leagues from 2000 until his retirement in 2022. Promoted to crew chief in 2013, Barrett worked in 33 play-off series, including five World Series. He retired following the 2022 season.
Ronald Clarence Kulpa is an American umpire in Major League Baseball. He wears uniform number 46.
Daniel Ralph Iassogna is an American umpire in Major League Baseball. He joined the major league staff in 1999. In 2012, Iassogna worked his first World Series. He was promoted to crew chief for the 2020 season.
Brian Edward Runge is a former umpire in Major League Baseball who worked in the National League in 1999 and throughout both major leagues from 2000 to 2012; he wore uniform number 18, and previously 71.
Harry Hunter Wendelstedt III is an American baseball umpire who has worked in the National League in 1998–1999 and throughout both major leagues since 2000. His father Harry Hunter Wendelstedt, Jr. was an NL umpire from 1966 to 1998. Hunter Wendelstedt goes by his middle name to avoid confusion with his father.
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.
Alfonso Márquez is a Mexican umpire in Major League Baseball (MLB) who worked in the National League in 1999 and has worked throughout both major leagues since 2000. He was promoted to crew chief for the 2020 season, becoming the first full time Latino-born crew chief. Márquez wears uniform number 72, a number he shared with friend and National Hockey League linesman Stéphane Provost.
Mark Patrick Wegner is an American Major League Baseball umpire. He worked in the National League from 1998 to 1999, and throughout both major leagues since 2000. He was promoted to Crew Chief for the 2018 MLB season when Dale Scott retired after the 2017 MLB season.
Philip Cuzzi is an American professional baseball umpire in Major League Baseball (MLB). He worked as a reserve umpire in the National League (NL) from 1991 to 1993 and returned to the NL in 1999. Since 2000, he has worked in both major leagues. Cuzzi wore number 99 when his career started; he now wears number 10.
Scott Adam Barry is currently an American umpire in Major League Baseball (MLB). Scott made his debut as an MLB reserve umpire in 2006, and 2011 was his first full-time season as an MLB umpire. He lives in Quincy, Michigan.
Todd Frederick Tichenor is an American professional baseball umpire. He became a Major League Baseball reserve umpire in 2007 and was promoted to the full-time MLB staff in 2012. He wore number 97 until the 2014 season, when he switched to number 13.
Robert Paul Drake is an American umpire in Major League Baseball. He was named to the Major League staff in 2010, and wears uniform number 8.
Michael William Muchlinski is an American Major League Baseball umpire. He umpired his first Major League game on April 24, 2006, and was officially hired by MLB prior to the 2014 season.
Manuel Augusto González is a Venezuelan umpire in Major League Baseball (MLB). He made his major-league umpiring debut on May 17, 2010, filling in for John Hirschbeck, becoming the first Venezuelan umpire in MLB history.
David Ross Rackley is an American Major League Baseball umpire. He made his Major League umpiring debut on August 13, 2010. He wears uniform number 86.
Christopher Robert Segal is an American Major League Baseball (MLB) umpire. He wears number 96. He made his MLB umpiring debut in 2014.
Chad Robert Whitson is an American umpire in Major League Baseball (MLB) who was hired to the full-time staff in 2019 and wears number 62. He was born in Dublin, Ohio. He made his MLB debut on May 15, 2014. He has also umpired in the Gulf Coast League, the Appalachian League, the South Atlantic League, the California League, the Eastern League, the International League, and the Arizona Fall League.
