Toronto Maple Leafs goaltender Anthony Stolarz will be sidelined four to six weeks after he undergoes knee surgery.

Maple Leafs general manager Brad Treliving said Tuesday that an MRI revealed no structural damage for Stolarz, who leads the league in save percentage with .927, but that his knee has a loose body that looks like a "little pebble."

"It's in the wrong spot," Treliving said. "We waited for a few days to see if it would move. But it doesn't allow him to get full range of motion, so it's got to be removed."

Stolarz was placed on injured reserve Sunday, three days after he sustained a lower-body injury in the first period of the Maple Leafs' 3-2 win against the Anaheim Ducks. He sat out Toronto's 4-2 loss to the Detroit Red Wings on Saturday and was ruled out of Sunday's 5-3 win over against the Buffalo Sabres before being placed on IR.

The Maple Leafs will rely on goaltenders Joseph Woll and Dennis Hildeby in the absence of Stolarz.

Stolarz, 30, is 9-5-2 with a 2.15 goals-against average and that .927 save percentage in 17 games (all starts) this season.

He is 52-36-11 with a 2.61 GAA and .916 SP in 125 career games (100 starts) with the Philadelphia Flyers, Edmonton Oilers, Anaheim Ducks, Florida Panthers and Maple Leafs.