Thornton tore the ACL and MCL on April 2 in Vancouver but still returned to play San Jose's final four playoff games in a first-round loss to Edmonton. The Sharks say Thornton will have the operation Monday and there is no timetable for when he will be healthy again.
Thornton, 37, can become an unrestricted free agent this summer, putting his future in San Jose in question. He has been the face of the Sharks, along with fellow 37-year-old pending free agent Patrick Marleau. Both players said at locker cleanout day that they would like to return.