IRVING -- Dallas Cowboys leading tackler Sean Lee's season-ending injury will put head coach Jason Garrett's "next man up" theory to the test.
Lee has been placed on injured reserve and will miss the rest of the season because of a right big toe injury, and losing Lee's production and leadership will put a strain on the Cowboys' fourth-ranked defense.
"He's the leader of our defense. He makes the [defensive play] calls," said Cowboys Head Coach Jason Garrett Wednesday. "He plays the right way… he's a bell cow for us."
Lee leads the team in tackles with more than 25 more than the next closest player on the defense, fellow inside linebacker Bruce Carter. Carter will now be called upon to call the defensive signals.
Coach Jason Garrett said Wednesday that Lee will have surgery in the "next week or so." Garrett says an MRI showed ligament damage that will require the surgery and end hopes of Lee possibly being able to return in four to six weeks.
Lee, a third-year pro, has also emerged as a leader in the locker room. His play on the field has earned him the respect of his teammates and allowed him to become one of the guys who can hold others on this team accountable.
"He goes about it the right way and he's an outstanding person, as well," Garrett said. "We love everything about him. It's obviously unfortunate and disappointing he had the injury."
Veteran Dan Connor will take over Lee's starting spot, but he's proven to be vulnerable in pass coverage. The Cowboys signed veteran linebacker Ernie Sims, who played 13 games last year for Indianapolis.
Dallas also put punter Chris Jones on injured reserve Wednesday.
The Cowboys host the Giants (5-2) this Sunday.