"He's going to have surgery on the knee so obviously he is done for the year," said Coach Mike Martz on the Rams' Web site. "It will take about four months to recover and rehab that thing. I just feel bad for J.B. I really do. He really was at the point where he was an exceptional player and was really looking forward to the season and that's devastating to anybody."
Butler suffered the injury on the first day of training camp in July. He said he felt something in the knee, but finished the practice and after still feeling pain underwent an MRI exam, which revealed the tear.
Butler, 26, made in five of the team's six interceptions -- an NFL low for the team -- and his 79 tackles also were a career-high.