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.
Aaron John Boone is an American former baseball infielder and current manager of the New York Yankees of Major League Baseball (MLB). He previously played in MLB for 13 seasons from 1997 through 2009. As a player, Boone is most recognized for his 2003 campaign with the Yankees, during which he was an All-Star and hit the winning walk-off home run of the 2003 American League Championship Series.
Douglas Leon Eddings is an American professional umpire in Major League Baseball.
Jerry Blake Layne is an American umpire in Major League Baseball who has worked in the National League between 1989 and 1999, and throughout both major leagues since 2000. He wore uniform number 24 in the NL, but when MLB merged the AL and NL umpiring staffs in 2000, Layne was forced to switch to number 26, as AL umpire Al Clark, who also wore 24, had more seniority. When Clark was fired midway through the 2001 season by MLB, Layne reclaimed number 24 and has worn it ever since. With the retirements of Joe West and Gerry Davis in 2022, Layne became MLB's most senior active umpire.
Martin Robert Foster is an American retired Major League Baseball umpire. After first working in the American League in 1996, he was added to the MLB umpiring staff in 2000. Foster retired following the 2022 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.
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.
Laurence Henry "Dutch" Rennert Jr. was an American umpire in Major League Baseball who worked in the National League from 1973 to 1992.
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.
William Scott Miller is an American Major League Baseball umpire who began his career in the American League in 1997. Miller wears number 26. He has been a crew chief since the 2014 season.
Mike G. Everitt is a retired Major League Baseball umpire, who wore number 57. He worked in the American League from 1996 to 1999 and throughout both major leagues from 2000 to 2019.
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.
Victor Joseph Carapazza is an American Major League Baseball umpire. He wears uniform number 19, and previously wore uniform number 85.
Carlos Torres Nuldis is a Venezuelan professional umpire in Major League Baseball (MLB). He made his major league debut in 2015.
Christopher Robert Segal is an American Major League Baseball (MLB) umpire. He wears number 96. He made his MLB umpiring debut in 2014.
Ramon Silvestre De Jesus Ferrer is a Dominican professional baseball umpire. He made his Major League Baseball (MLB) debut on April 22, 2016, thus becoming the first MLB umpire from the Dominican Republic. De Jesus wears number 18, which was most previously worn by former umpire Marcus Pattillo.
Jon Stephen Byrne is an Australian former Major League Baseball (MLB) umpire. He made his debut on 16 May 2014, becoming the first MLB professional umpire to have been born in Australia. Australian second baseman Joe Quinn had acted as a substitute umpire for two National League games; one each in 1894 and 1896.
Benjamin Joseph May is an umpire in Major League Baseball (MLB). He has worked in MLB since 2014, and wears number 97 on his uniform.
John Libka is a Major League Baseball umpire.
