Nick Foligno needed help getting off the ice during the opening period Saturday against the Tampa Bay Lightning.
He left the game for the Bruins after a collision in front of the Tampa net, and during the second period, Boston announced he was ruled out for the remainder of the game.
Bruce Cassidy doesn't anticipate he'll be back for Monday.
"A lower body (injury) obviously, you saw his leg kind of buckle there. So I suspect we'll have a better update tomorrow," Boston's head coach said after the 5-2 win.
"We knew right away he wouldn't return, how bad it is, I think you give us a couple days but my guess is we'll probably rule him out for Monday."
Foligno was on the attack when Callan Foote tried to get between him and the net, but the Lightning defender fell and landed on Foligno's leg, trapping it awkwardly.
Here's the play where it all went down.
The Bruins face the Washington Capitals in D.C. on Monday.
