Lupul was kept out of Thursday’s game against Boston due to what was then described as a “lower-body” injury suffered in Tuesday’s victory over the Calgary Flames.
A game-time decision on Saturday, Lupul played just 12:07 in the Leafs’ 4-2 home loss to the Winnipeg Jets before leaving the game. He did not return.
The 30-year-old finishes the 2013-14 season with 22 goals, 22 assists and 44 penalty minutes in 69 games played.
Lupul’s campaign marked his second as a 20-goal scorer for the Maple Leafs.
Due to various injuries, the forward hasn’t played 70 games in a single season since 2008-09, when he was a member of the Philadelphia Flyers.
Toronto, which sits three points out of wild card spot in the Eastern Conference, plays Tuesday at Tampa Bay, Thursday at Florida and Saturday at Ottawa.
Lupul’s surgery will sideline him for an estimated three weeks, but barring an improbable run and a collapse by both the Columbus Blue Jackets and New Jersey Devils, who each have a game in hand, the Leafs will not qualify for the post-season.