The Angels' reliever had been finger-pointed by Washington Manager Frank Robinson in Tuesday's contest between the Angels and Nationals. Robinson asked umpires to check Donnelly's glove before he threw a pitch in the seventh inning.
Umpires found pine tar on the glove, violating rule 8.02b, which prohibits a pitcher from having a foreign substance on his person or equipment.
A bench-clearing brawl almost erupted after a shouting match between Robinson and Anaheim Manager Mike Scioscia. Both of them were hit with one-game suspensions.
No punches were thrown during the incident and Donnelly has appealed. The appeal will delay his punishment.