The forward, who has 21 points (eight goals, 13 assists) in 43 games this season, was injured in the first period of a 3-2 loss to the Dallas Stars on Thursday.
"We'll have more of an update on his timeline once the procedure is completed, but he is expected to miss at least eight weeks," Maple Leafs coach Sheldon Keefe said Friday.
Keefe also said defenseman Morgan Rielly, who has been out since Jan. 12 with a broken foot, could return next month. Rielly has 27 points (three goals, 24 assists) in 46 games.
"I believe in the next week or so he'll be progressing to weight-bearing and starting to move forward with his rehab plan," Keefe said. "We're still looking at towards the end of March (for a return)."
The Maple Leafs also are without defenseman Cody Ceci (ankle) and forward Ilya Mikheyev (wrist).
"It does present challenges, it affects your depth, but I think we've talked about it more than enough times that it is part of the game and part of the League," Keefe said. "Everybody goes through it. For the most part, most of the teams we are playing are going through similar types of things."
The Maple Leafs (30-20-8), who play at the Ottawa Senators on Saturday (7 p.m. ET; CBC, SNO, SNW, SNP, NHL.TV), are third in the Atlantic Division, two points ahead of the fourth-place Florida Panthers.
NHL.com independent correspondent Dave McCarthy contributed to this story
