Pittsburgh Penguins captain Sidney Crosby has been diagnosed with a concussion, general manager Jim Rutherford announced Monday.
Head coach Mike Sullivan revealed the injury happened at practice Friday, and there is no timeline for his return.
Pittsburgh opens their season Thursday versus Washington.
Crosby has dealt with concussions in the past, and was forced to miss significant time in 2011 and 2012 while dealing with the lingering effects.
The news couldn't come at a worse time for Crosby and the Penguins, as the world's best player has been on an absolute tear since Sullivan took over as Pittsburgh's head coach.
Crosby, 29, finished the last regular season with 85 points, while adding another 18 in the playoffs, en route to his second Stanley Cup and the Conn Smythe as playoff MVP.
He picked up right where he left off in September, captaining Team Canada to a World Cup of Hockey title and earning tournament MVP honors with 10 points in six games.
