pinch hit, v. — Green’s Dictionary of Slang

pinch hit v.

[baseball jargon pinch-hit, to substitute for a batter, esp. at a crucial point in the game]

to act as a substitute, esp. in an emergency.

1918		‘Commander’ Clear the Decks! 174: Got the name for being a pinch hitter [...] he gained the reputation of being able to patch up his engines.
1926		T.A. Dorgan in Zwilling TAD Lex. (1993) 64: Listening to the two janes who are pinch hitting for the editor of the help or hinder page.
1938		W. Winchell On Broadway 14 Mar. [synd. col.] Did you know that Dinty Doyle, the radio columnist, was given hardly any notice to pinch hit for George McCall.
1944		in W.C. Fields By Himself (1974) 494: Miss Monti [...] is at present doing her stuff in a chapeau emporium up in Santa Barbara, pinch hitting for a lady that has a 50% interest in the shop.
1953		S. Bellow Augie March (1996) 87: If your friend Klein [...] will pinch-hit for you here [...] you can go and have an excursion.
1982		R.M. Brown Southern Discomfort (1983) 216: Linton Ray, high in his pulpit, pinch-hit for God.
1992		D. Burke Street Talk 2 172: Can you pinch hit at the meeting for me? I have to leave town suddenly.