NASHVILLE, Tenn. -- Titans linebacker Keith Bulluck has a torn left anterior cruciate ligament and will miss the remainder of the season, and outside linebacker David Thornton will have season-ending shoulder surgery later this week.
Titans coach Jeff Fisher announced Monday that test results show Bulluck tore his left ACL during the third quarter of Sunday's 27-24 overtime victory over Miami Dolphins in what might have been his final game with the franchise that drafted him 30th overall in 2000. The Titans planned to place Bulluck on injured reserve Monday, and the linebacker will have surgery within two weeks.
Thornton was deactivated for the game against the Dolphins, but the Titans (7-7) had hoped he might return.
Fisher called the losses devastating to Tennessee's defense.
"David was playing very well this year when he was able to play, and Keith, Keith is kind of the cornerstone of our defense, and he has been for so many years," Fisher said. "I don't need to speak about the consecutive starts and production. He's gone from AFC Defensive Player of the Week to gone for the remainder of the season."
Bulluck was the AFC Defensive Player of the Week after he intercepted two passes during a 47-7 rout of the St. Louis Rams on Dec. 13.
A 10-year veteran, Bulluck is the franchise's top tackler this season in the final year of his contract. He made his 127th consecutive start Sunday, second only to the Washington Redskins' London Fletcher (148) among linebackers. Bulluck led the Titans in tackles last season and had a team-high 113 tackles entering the game against the Dolphins.
"It's a blow," Fisher said. "But we'll plug people in, and we'll go on. That's all we can do."
Rookie Gerald McRath started three games this season in place of Thornton. Colin Allred, a second-year pro out of Baylor, will replace Bulluck. Middle linebacker Stephen Tulloch will replace Bulluck making the defensive play calls and wearing the helmet communication device as he did once Bulluck was injured Sunday.
Fisher said the Titans will add some special-teams help to the roster, but he wouldn't discuss any possible names.
Losing Bulluck hurts most with the San Diego Chargers (11-3) visiting Friday night in a must-win for the Titans to keep their dwindling playoff hopes alive for the final week of the regular season. Bulluck's cover skills will be missed against Chargers tight end Antonio Gates, who already has 74 receptions for 1,071 yards this season.
"If I know both of them the way I think, I think they'll continue to have a part in the defense and be vocal with the guys on the field," center Kevin Mawae said.
Fisher wouldn't discuss Bulluck's future with the Titans. The linebacker turns 33 in April and will spend most of the offseason recovering from this injury.
"Those are things that will get worked out," Fisher said. "I think the thing to add here at this moment is the loss and what that does for us to this point and also emphasize when you lose a player in the starting lineup, your players have to step up and play, and that's what we expect to have happen."
Bulluck wasn't available Monday, but he posted on his Twitter account that "I ain't go'n out like this. My spirits r gr8." He later added that his rehab hobby will be learning how to play his guitar.