Mike Fisher for 105.3 The Fan | CBSDFW.com

IRVING, Texas (105.3 THE FAN) – The Dallas Cowboys braced themselves for “a fear-the-worst deal’ regarding middle linebacker Sean Lee’s left knee injury and may have gotten that Tuesday evening.

Sources told 105.3 The Fan that Lee’s MRI may show what medical experts call an “unhappy triad’’ – tears to his ACL, MCL and medial meniscus.

READ MORE: Parents Of North Texan & Former Marine Trevor Reed Want President To Stand Up For Their Jailed Son

Lee — considered by many to be a Pro Bowl-caliber player held back by injuries — was escorted off the Valley Ranch practice field during Tuesday’s opening of Dallas Cowboys OTAs. Sources close to Lee told 105.3 The Fan that he assumed an ACL tear based on the fact that he’d endured a similar injury to his right knee in college.

The Cowboys aren’t prepared to confirm the news. But sources say Lee may return to the doctor for a second opinion on the “unhappy triad’’ and maybe a second MRI on Wednesday.

Lee collided with rookie offensive lineman Zack Martin during the non-contact workout. Medical personnel tended to his leg and foot area before guiding him into the locker room. During that walk, the mild-mannered Lee lashed out at photographers jostling for position, asking loudly for “respect.”

Last August, Lee, 27, signed a six-year contract extension worth as much as $51 million – an incentive-heavy deal built to account for the fact that since entering the NFL in 2010, Lee has yet to play a full season.

READ MORE: Poll: Many Americans Would Keep Working From Home As Pandemic Eases

“I haven’t been healthy the last couple of years, and I know it’s my job to be on the field,” Lee said recently. “The key now is to be on the field for the entire year and contribute the entire year.”

Lee could now face a post-surgery recovery period of at least eight months. The Cowboys drafted rookie fourth-rounder Anthony Hitchens to back up Lee. The club could also consider available veterans like Jonathan Vilma, or shuffle the existing group of linebackers to give Bruce Carter, DeVonte Holloman or Justin Durant time inside.

(©2014 CBS Local Media, a division of CBS Radio Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)

Top Trending:

MORE NEWS: 3 Spectators Critically Injured After Vehicle Crashes Through Guardrail At Texas Race Track