Senators center Jason Spezza will miss six to eight weeks with a torn ligament in his right knee.
The team announced Spezza's status on Wednesday after an MRI on Tuesday night showed damage to his medial collateral ligament.
Spezza was injured during the third period of a 3-2 loss in Toronto on Monday. He got tangled up with Leafs forward Lee Stempniak during a faceoff and had to leave the game.
He has five goals and 14 assists in 30 games this season.