Jake Long suffered a torn ACL and MCL in the St. Louis Rams' Week 16 win against the Tampa Bay Buccaneers.
Long will undergo season-ending surgery.
"With respect to the fact that also the MCL is included, surgery will probably be delayed four to six weeks," Jeff Fisher said. "He takes very good care of himself. He knows and understands what's ahead. Obviously he is shocked right now but he's indicated to us that he'll be back and good to go."