Pittsburgh Penguins captain Sidney Crosby left Game 3 of his team's playoff series against Washington and did not return after taking a hit to the head from Capitals defenceman Matt Niskanen.

Penguins head coach Mike Sullivan did not offer an update on Crosby's status afterwards, saying that the star would be evaluated overnight.

The Capitals won the game 3-2 in overtime to cut Pittsburgh's series lead to 2-1.

The Penguins were in Washington's end of the ice when Niskanen cross-checked Crosby across the face with his stick. Crosby was skating by Washington goaltender Braden Holtby when he turned and faced Niskanen.

Niskanen raised his stick and hit Crosby flush. Crosby was on the ice in obvious pain for several minutes before exiting slowly under his own power.

Niskanen was given a five-minute major penalty and a 10-minute game misconduct.

"I wasn’t extending trying to hit him in the head...I wasn't even trying to crosscheck him with a serious amount of force," Niskanen told reporters after the game. "A collision was going to happen there in the crease."

Crosby entered Monday's game tied for second in playoff scoring with 11 points, including two goals in a Game 1 victory over Washington.