Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
pinch-hit (n., v.), pinch hitter (n.)
In baseball the verb means “to bat for another player in hopes of being more successful than that player is likely to be”; the player who does so is a pinch hitter, and what pinch hitters hope to get are pinch hits—which will let them reach first base and probably advance runners already on base. The figurative use is limited to the verb, meaning “to substitute for another in an emergency, (in a pinch),” and to the noun pinch hitter, which is what that substitute is called: She pinch-hit for me at the circulation desk and then had to call for another pinch hitter when the regular evening person didn’t show up. The baseball uses of these terms are the argot of the game; the figurative generalized uses are Standard Informal and Conversational.
