The Ottawa Senators announced that captain Erik Karlsson had surgery Wednesday to repair torn tendons in his left foot.
"The tears, which occurred during this year's Stanley Cup Playoffs, were found during an MRI as part of an extensive medical evaluation following the season," Senators general manager Pierre Dorion said.
Dorion said the team expects Karlsson to miss about four months, which would allow him to return right around the start of the regular season.
Karlsson, 27, had 18 points in 19 games and played 28 minutes per game in the playoffs. Ottawa lost in the Eastern Conference final to the eventual Stanley Cup champion Pittsburgh Penguins.
Karlsson said he had been playing through hairline fractures in his left heel after the first round.