Senators captain Erik Karlsson had surgery on Wednesday to repair torn tendons in his left foot.
The injury happened during the Senators' playoff run and was discovered during an MRI as part of a season-end medical evaluation, the team said in a statement.
Karlsson had the surgery in Charlotte, N.C.
His recovery is expected to take about four months.
"This timeline leaves us hopeful that Erik will be fully recovered and healthy to start the 2017-18 regular season," the statement said.
Karlsson also played through two microfractures in his foot, which were sustained when he blocked a shot in a game against the Philadelphia Flyers near the end of the regular season.
Despite the injuries, Karlsson led the Senators in scoring during their playoff run to within one goal of the Stanley Cup Final, and was the only non-finals player to receive a vote for the Conn Smythe Trophy as playoff MVP.
