ARLINGTON, Texas -- Sean Lee spent Wednesday at the Dallas Cowboys' Valley Ranch practice facility, attempting to help the young linebackers on the roster prepare to try to replace him after he suffered a left knee injury that is expected to sideline him the entire 2014 season.
That show of character, along with Lee's talent, will make him extremely difficult for Dallas to replace.
"Sean is a very special guy," coach Jason Garrett said during the team's home run derby at Globe Life Park to raise money for the Salvation Army. "He is a heck of a football player and [there are] a lot of reasons for that. A lot has to do with his athletic ability but also the approach that he takes to the game. He is a student of the game. He is a great teammate. He is a great team leader.
"We certainly love the guy. We want the best for him."
Garrett said the Cowboys are continuing to evaluate Lee and aren't ready to make "any definitive conclusions" about the severity of the injury, but several of his teammates confirmed that the star middle linebacker who finished the last two seasons on injured reserve suffered a torn ACL.
It's a heartbreaking loss for the Cowboys, leaving a major leadership and production void in the middle of a defense that allowed the most yards in the NFL last season and saw the departures of defensive end DeMarcus Ware and defensive tackle Jason Hatcher this offseason.
"First and foremost, you hurt for him," tight end Jason Witten said. "Obviously, it hurts us as a football team. I've seen a lot of work go in, a shared commitment with him, and then obviously just see him do a lot of work.
"To see him be in this situation he is and the way it happened, football is a tough game. It definitely hurts. Your heart hurts for him, because of how much he puts in and how much he cares about it. That was a tough blow."
Rookie Anthony Hitchens, a fourth-round pick, manned the middle linebacker spot with the starting defense during Thursday's workout. DeVonte Holloman, a sixth-round pick in 2013 who performed well during an emergency start at middle linebacker in last year's season finale, also got work at the position. Justin Durant, the team's starting strong side linebacker until a severe hamstring strain ended his season early last year, isn't cleared to practice yet but is also a candidate to replace Lee.
Garrett indicated that the Cowboys wanted to evaluate the linebackers on their roster before considering adding a veteran linebacker to the roster. Potential fits in free agency include Jonathan Vilma, Rocky McIntosh, Pat Angerer and Brian Urlacher.
"Obviously, it's a huge loss to our team, especially our defense, but at the same time, guys have got to step up," weakside linebacker Bruce Carter said. "It's kind of bad to say, but we've been in this situation before. Guys have got to step up and just play their role."
Lee's injury occurred late in Tuesday's practice, the first of the Cowboys' OTAs. His left knee buckled when he planted his foot and tried to come back to tag DeMarco Murray on a screen pass during the non-contact workout. Guard Zack Martin inadvertently landed on top of Lee, but the injury happened before Martin locked up with the linebacker.
That leaves a gaping hole in the middle of the Dallas defense, no matter how much Lee tries to help his potential replacements.
"Man, it brought me down," receiver Dez Bryant said. "I was very emotional because of the fact that he's one of the guys that I highly respect in the NFL, especially on the Cowboys. Don't nobody work harder than Sean Lee. Just to see that happen to him, it's heartbreaking. I know the whole season, I'm going to have [Lee's number] 50 somewhere on me."