Cowen was sanctioned for making contact with the head of Sabres' rookie center, who had a big game with a goal and a shootout game-winner during the Senators' Tuesday loss.
Girgensons was hit with an elbow to the head while corralling a long pass in the attacking zone. Cowen wasn't penalized on the play but was cited by the NHL for the contact and taking an improper angle of approach.
Cowen received the first fine or suspension of his 121-game career.
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