Defenseman Miro Heiskanen was injured in the third period of the Dallas Stars’ 4-3 overtime victory over Vegas after taking a hit from Golden Knights captain Mark Stone.

Las Vegas’ Stone fell into Heiskanen’s left knee in an awkward collision, which forcing Dallas’ top defenseman out of the game.

The star defenseman will likely be out for months, if not the rest of the season. Expect the Stars to struggle in his absence, and to have a much better understanding of their roster when he returns.