Montreal Canadiens forward Max Pacioretty left Sunday's game against the Florida Panthers in the first period after crashing heavily into the boards.
Pacioretty was going to the net when Panthers defenceman Dmitry Kulikov knocked him off balance, causing him to fall awkwardly into the end boards.
He appeared woozy as he left the ice with the assistance of a member of the training staff.
After the period, the Canadiens announced Pacioretty would not return to the game.
Kulikov was assessed a minor penalty for intereference on the play.