It was another devastating injury for the ninth-year pro from Florida.
Peterson, who entered Sunday's game with 108 tackles, missed 11 games last season after tearing a chest muscle.
He was slumped over at his locker after Jacksonville's 24-17 victory Sunday and declined to comment. Several players and coaches stopped by to console him.
The Jaguars also could be without cornerback Rashean Mathis next week against Buffalo. Mathis strained his groin in the first half and did not return.
Copyright 2007 by The Associated Press