General manager Doug Wilson announced that Thornton had the operation Thursday to repair the MCL on his right knee. Thornton hurt the knee late in Tuesday night’s overtime loss to Winnipeg and Wilson previously said the injury will likely sideline Thornton for several weeks.
Thornton tore the ACL and MCL in his left knee late last season. He returned for four playoff games before undergoing off-season surgery.
The 38-year-old Thornton has played all 47 games this season and has 13 goals and 23 assists to rank second on the team in scoring.
Thornton is playing on a one-year, $8 million contract.