batterymate

noun

bat·tery·mate ˈba-t(ə-)rē-ˌmāt

plural batterymates

baseball

: a fellow member of a baseball battery (see battery sense 11) : the catcher who is paired with a pitcher or the pitcher who is paired with a catcher

a pitcher and his batterymate

He shares the responsibility for calling the game with the pitcher. But while his batterymate only faces the pressure once in four games, the catcher goes into the furnace nearly every day.—

George Cantor, Baseball Digest, January 1969

… his fellow pitchers and batterymates report for their first official workout of 1987 …—

Gary Ferman, Miami Herald, 21 Feb. 1987

When Mirabelli settled in behind the plate to catch his batterymate's frustrating knuckleball even he had trouble collecting them in his catcher's mitt.—

Michael Vega, Boston Globe, 24 May 2006