Ronald Leary practicing with knee condition

IRVING, Texas -- Undrafted rookie free agent guard Ronald Leary from Memphis met with Cowboys doctors Thursday to review the results of an MRI on his left knee that revealed he has osteochondritis dissecans (os-tee-o-kohn-DRY-tis DIS-uh-kanz).

Known as OCD, it's a joint condition where a piece of cartilage, along with a thin layer of the bone beneath it, comes loose from the end of a bone.

According the Mayo Clinic, it's caused by reduced blood flow to the end of a bone. OCD occurs most often in young men, particularly after an injury to a joint. The knee is most commonly affected, although OCD occurs in other joints such as the elbow, shoulder, hip and ankle.

Last May, Leary underwent surgery to repair a torn meniscus in his left knee but he didn't miss any games last season for Memphis. But at the scouting combine this spring, several NFL teams backed away from Leary fearing his knee wouldn't hold up long-term.

"I know personally there’s nothing wrong with it," Leary said after Friday's first practice session for rookies and selected second-year players at Valley Ranch. "I just have to go out there and prove everybody wrong that I'm healthy."

This spring, Leary performed well at Memphis' pro day and held a private workout for Cowboys offensive line coach Bill Callahan.

The Cowboys are taking a risk with Leary because there's no telling when the knee will give way. Leary said several NFL teams called him during the draft to say they weren't going to select him, but rather offer him a free agent contract.

Leary was targeted by the Cowboys in the middle rounds and last week owner/general manager Jerry Jones said the team was taking a risk by waiting for the guard to not get drafted.

"[I was] disappointed because [you] always want to go higher," Leary said of his draft status. "I got a chance to be a Dallas Cowboy, you can't be disappointed by that. It's the greatest organization in the NFL, it didn’t happen the way I wanted it too but I'm loving it."

Leary, who didn't practice with any braces on Friday, said he doesn't need any future micofracture surgery, which might put a player's career on hold for at least one year.

"I try not to think about it because nothing is wrong with it" he said. "But I play with a chip on my shoulder, just everybody is doubting me and they say I'm not going to make it. So I'm out here to prove everybody wrong."