OXNARD, Calif. -- Dallas Cowboys cornerback Morris Claiborne left Wednesday's practice after twisting his right knee.

The team's medical staff was going to evaluate the knee after the practice. Owner/general manager Jerry Jones said he didn't know the severity of Claiborne's injury but was not as concerned as he was the previous day about rookie defensive end DeMarcus Lawrence, based on the initial evaluation.

X-rays showed Lawrence had a broken bone in his right foot that will sideline him from eight to 12 weeks. Jones said he did not know if Claiborne's injury was serious enough to need an MRI exam.

"[Head athletic trainer] Jim Maurer felt pretty good about it," Jones said. "Our head trainer looked at it. Certainly it was enough to get examined. He's been one of our highlights."

Claiborne said his knee twisted when his cleats got caught in the ground as he attempted to make a play on the pass. He did not take another rep after the play, a back-shoulder fade to Terrance Williams in 7-on-7 drills, watching the rest of the practice from the sideline.

The Cowboys had been encouraged by Claiborne's performance early in camp. There was legitimate hope that this could be a breakout campaign for the 2012 sixth overall pick, who was limited by injuries in his previous two training camps.

Asked if he feels jinxed, Claiborne said, "I don't know. I'm fixin' to go find out."