Jonathan Bernier, who sported a .923 save percentage in 55 games for the Leafs this season, will have sports hernia surgery on Wednesday and is expected to need two to three weeks of rehabilitation.
The injury also cost Bernier five games in March. He said he would be healthy for training camp in September.
"I felt pretty good," he said. "It was sore but my range, my stretching was fine. I think a lot of players play through that."
On April 3, Bernier suffered what head coach Randy Carlyle said was a sprain of the medial collateral ligament in his left knee against the Boston Bruins and missed the team’s final four regular-season games.
Bernier, who hails from Laval, Que., had a 26-19-7 record this season with a 2.68 goals-against average.
The Leafs missed the playoffs after posting a dismal 6-14-2 record down the stretch.
"We all know as a group that we didn't play to our potential all year," said Bernier. "We waited too long to turn the switch on and start playing some good hockey."
Last June, Toronto acquired Bernier in a trade from Los Angeles, sending forward Matt Frattin, goalie Ben Scrivens (since dealt to Edmonton) the Leafs’ second-round pick either this summer or in 2015.
Bernier emerged as a No. 1 netminder in Toronto for the first time in his four-plus NHL seasons, outplaying James Reimer, who was a big reason the team advanced to the Stanley Cup playoffs the previous campaign.
In 117 NHL regular-season contests, Bernier is 55-39-13 with a 2.51 GAA, .918 save percentage and seven shutouts.
He was the 11th overall pick in the 2006 draft, the same year the Leafs took Reimer 99th overall.
Elsewhere on the Leafs' injury front, forward Joffrey Lupul says he's recovering after knee surgery and doesn't expect his off-season training to be impacted.
Forward Phil Kessel says he was "good enough" through the end of the season despite a bruised right foot while James van Riemsdyk wouldn't reveal any specifics on his injury.