opposite field hitter (1938)

“The moral of this story is never to throw an opposite field hitter a slow ball, unless you certain that he is an exception to the rule, or unless your third or first baseman has has teeth insured.” Paul Richards, “Finding Batters’ Weaknesses Takes Keen Observation,” Birmingham News, February 9, 1938, p10
NOTE: Richards was player-manager of Atlanta in Southern Association at the time.

No earliest use given in 2009 Dickson Baseball Dictionary