IRVING, Texas — Dallas Cowboys coaches won't be talking to linebacker Sean Lee through his helmet mic anymore this season.
Instead, he might be in their ears all the time on the sideline.
Lee is out for the rest of the season with ligament damage in his right big toe, an injury that will require surgery. Coach Jason Garrett said Wednesday an MRI showed the extent of the damage and the team's leading tackler and on-the-field defensive coordinator was placed on injured reserve. He will have surgery in about a week.
Lee was injured in the second half of last weekend's 19-14 win against Carolina, and he was already donning a headset before the game ended.
"I remember seeing him on the head phones on the sidelines," said his replacement, Dan Connor, an offseason pickup in free agency. "He was really coaching out there. There's no reason why he shouldn't."
It's not the first time Lee has been sidelined by a significant injury. He missed a year with a torn knee ligament at Penn State, and he could have missed a significant stretch last year with a dislocated wrist. He ended up sitting for a game and a half before coming back and playing the rest of the season with a cast.
Cowboys owner Jerry Jones said Lee didn't want to believe he needed season-ending surgery this time, but ultimately knew better.
"He has such an intensity about him," Garrett said. "He said, `You know, I'm not getting down. I'm ready to go I'm going be part of this football team and we're going to get this thing fixed. I'll be back before you know it.'"
The Cowboys moved up in the draft to take Lee in the second round in 2010, and he was still available in part because of his history with injuries. He started 15 games last year, finishing with 105 tackles and tying for the team lead with four interceptions. He had 58 tackles in six games this year and another interception.
"I can't tell you how well he's been playing since he's been our starting inside linebacker," Garrett said. "He's a bell cow for us and a guy that really everybody on our defense and football team looks up to."
Connor will replace Lee as a starter heading into Sunday's home game against the Giants, but the Cowboys signed veteran linebacker Ernie Sims, who played 13 games last year for Indianapolis. Bruce Carter, the other Dallas starter at inside linebacker, will call most of the defensive signals.
"It's something that definitely stings when you lose your middle linebacker, but at the end of the day, they're not going to cancel or postpone the games because Sean Lee got hurt," defensive end Marcus Spears said. "You don't have time to dwell on it."
The Cowboys are fourth in the NFL in total defense and made two key stops in the fourth quarter at Carolina to help Dallas rally from a 14-13 deficit. Garrett showed faith in the defense by running on third-and-9 to set up the go-ahead field goal with still 3:25 remaining.
Garrett made that decision after the injury to Lee, who also missed two games his rookie season with a hamstring problem.
"This is not new," Garrett said. "This has happened a lot. And you rally around it. Sean Lee's the kind of guy that will stay engaged in our football team, and we appreciate that about him."
Dallas also put punter Chris Jones on injured reserve and signed safety Charlie Peprah. The Cowboys added linebacker Jerry Brown to the practice squad a week after he was let go by Indianapolis.