At Baseball Daily Digest, I paw through the pitching performances of position players since 1980.
Arguably the worst performance is attributed to Frank Menechino with the Oakland Athletics. In a game that the A’s would lose 18-3 to the Colorado Rockies, Frank came in the bottom of the eighth inning, replacing T.J. Matthews who had allowed a lead-off walk and a double.
Menechino allowed four singles, a double, and a home run, leading to six Rockies runs. He was saved, mercifully, when Butch Huskey grounded into a 4-3 double play to end the inning.