The incident occurred in the third period of Washington's 8-4 win in Montreal on Saturday. Pezzetta hit Oshie's head as he finished a check after the Capitals forward had made a play to move the puck out of Washington's zone.
Pezzetta was assessed a minor penalty for an illegal check to the head on the play. The Canadiens forward, who had no history of discipline, will forfeit $7,500 in salary.
Pezzetta will be eligible to return when the Canadiens visit Ottawa on April 23.