Coach Bob Boughner announced the injury Monday, adding that Luongo will not need surgery. The Panthers placed Luongo on injured reserve Sunday after he left their season opener Saturday night.
Luongo started 33 games for Florida last season and went 18-11-2 with a 2.47 goals-against average and .929 save percentage. He missed more than two months with a groin injury last season.
The 39-year-old is signed through the 2021-22 season at a salary-cap hit of $5.3 million.
Florida recalled goalie Michael Hutchinson from Springfield of the American Hockey League and will lean on James Reimer in Luongo's absence. Bougher says the Panthers are confident in Reimer because of his starting experience in the NHL.