The move ends Pace's 2007 season.
Pace, a seven-time Pro Bowl choice, suffered his injuries Sunday with just under two minutes remaining in the first half of the Rams’ 27-13 loss to Carolina.
It is the second straight season the former Ohio State all-American -- a first-round pick by the Rams in the 1997 NFL Draft -- has had his season cut short by injury. He missed half of the 2006 season due to a torn left triceps and a concussion.
"I feel real bad for Orlando," Coach Scott Linehan said. "He worked very, very hard to get himself back from his triceps injury a year ago (and) probably is in the best shape he's been in a number of years."
The 6-foot-7 inch, 325-pounder has played in 144 NFL games.