The Jaguars' injured reserve list is getting crowded.
Jacksonville now has 15 players on the list after adding three Monday -- cornerback Rashean Mathis, offensive tackle Eben Britton and linebacker and special teams player Kyle Bosworth.
The Britton move was expected, as he hasn't played in a month since his back started bothering him the morning of the Pittsburgh game. He hasn't been seen on the practice field or in the locker room recently.
But Mathis' injury was unexpected, as he suffered it on a play when he had no contact.
"On film, you can see it go out. No contact. Foot planted on the turn, knee shifted," coach Jack Del Rio said.
Mathis had an MRI exam Monday that revealed a torn left anterior cruciate ligament, and he will undergo surgery.
When it was noted it was something of a downer to lose a key play after a victory, Del Rio said, "Well, it's just what it is. It's life in the NFL. It's a tough business. It's tough for guys to get the news that they're going on IR, but as a football team, we're going forward doing the best we can.
"He's a good football player. He was having a good year for us."
The injury also raises questions about whether Mathis, a Jacksonville native, has played his last game for the team.
He will be a free agent at age 31 next March, and the Jaguars had not entered into negotiations about extending his contract.
The injury also could hurt Mathis' value on the free agent market, although it could make it easier for the Jaguars to keep him if other teams aren't bidding on him.
It was the most serious injury of Mathis' nine-year career. He was drafted in the second round out of Bethune-Cookman in 2003.
Mathis was a team leader and co-player rep on a young team, and his teammates talked about how much he'll be missed.
Drew Coleman, signed as a nickel back this year, said, "Oh, man, it's always tough to see any of your teammates go down. But it's different with Rashean with him being one of the leaders of this defense. Words can't explain how hard I've seen this whole secondary work to get to the point where we are right now. For him not to continue to be a part of it was definitely heartbreaking, something you wouldn't wish on anybody. He was doing such a great job of being that leader, that guy that everybody looks up to play in and play out. He's always been there for us."
Defensive end Jeremy Mincey added, "He's one of the best of the league at man-to-man coverage. The future was looking bright for him. That's a huge loss. He's definitely a veteran voice we need out there."