Sidney Crosby lying face-down on the ice is the Penguins’ worst nightmare.

Crosby, Pittsburgh’s captain and best player, left Game 3 of his team’s playoff series against Washington after taking a hit to the head from Capitals defenseman Matt Niskanen.

The Penguins were in Washington’s end of the ice when Niskanen crosschecked 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.

Crosby entered the game tied for second in scoring for Pittsburgh with 11 points, including two goals in Pittsburgh’s Game 1 victory over Washington.

The two-time NHL MVP has suffered from concussions in the past, missing the final 41 games of the 2010-11 season and the first 20 of the next season. After just seven games, Crosby’s symptoms returned and he was sidelined for another four months.

The 29-year-old also missed the first six games of this season with a concussion, including the season opener against the Capitals.