Cowboys’ defense couldn’t afford to lose Sean Lee

When the best player on your defense misses at least four or five games per season, it’s as good a reason as any for being awful on that side of the ball. Middle linebacker Sean Lee suffered a season-ending knee surgery three months before the start of the season Tuesday.

The Cowboys in-house options — Devonte Holloman and rookie Anthony Hitchens — aren’t terribly attractive. This defense couldn’t afford to lose Lee, although they do just that every season.

The Cowboys selected Lee in the second round of the 2010 draft because  he had tremendous value. They didn’t let it bother them that Lee missed an entire season at Penn State because of surgery to repair his anterior cruciate ligament. It was probably a risk worth taking based on how good Lee has been when healthy.

Still, the red flags were there. For all his heart and determination, Lee has always been undersized. He works as hard as anyone on the team, but his body can’t withstand all the punishment.

He has the type of intangibles that can transform a defense. But you can’t lead a defense while rehabilitating an injury. Now you know why the Cowboys were poised to take an inside linebacker such as Ryan Shazier in the first round. They weren’t going to demote Lee, but they may have moved him to the weak side.

The Cowboys took risks on both Lee and fellow linebacker Bruce Carter in successive drafts. There’s a decent chance neither player will hold a starting job by the end of the 2014 season.

Maybe the Cowboys should learn from teams that shy away from medical risks. Players with a history of injuries nearly always keep getting injured.

Lee signed what appeared to be a very team friendly contract before the 2013 season. Now, the contract looks lop-sided in Lee’s favor.

Lee should be entering the prime of his career in the NFL. It just doesn’t feel like it.