John Bertrand Conlan
- Bats Left, Throws Left
- Height 5' 7½", Weight 165 lb.
- High School De La Salle Institute
- Debut July 6, 1934
- Final Game September 29, 1935
- Born December 6, 1899 in Chicago, IL USA
- Died April 16, 1989 in Scottsdale, AZ USA
Conlan played most of his career in the upper minors and was going to retire but the White Sox needed him in 1934 due to injuries to their outfielders. He got into 128 games with the White Sox, beginning at age 34. During his minor league career he was known as "John Conlan."
He got his start as an umpire in 1935 when umpire Red Ormsby suffered heat prostration during a doubleheader in St. Louis. Conlan was sitting out the game with a sprained thumb and he officiated the second game in his White Sox uniform. Conlan went down to the New York-Penn League as an umpire from 1936 to 1937, then served in the American Association from 1938 to 1940. Conlan worked the National League from 1941 to 1965 (serving 15 games as a substitute umpire in 1965).
He got his nickname from a player named Jocko Conlon. Conlan was often confused for Conlon.
- Baseball Hall of Fame: Class of 1974