OXNARD, Calif. -- Dallas Cowboys cornerback Morris Claiborne will not practice on Thursday because of a sore tendon in his right knee, according to a source.

Claiborne suffered the injury during a seven-on-seven drill when his cleats got caught in the ground as he attempted to break up a back-shoulder throw to Terrance Williams. He remained on the ground for a few minutes and was examined by the team’s medical staff but did not take another snap the rest of the practice.

The hope is rest and treatment will be the only thing Claiborne needs. Claiborne missed time in his first two training camps as well.

"It’s just tendonitis," Claiborne said after the morning walkthrough. "I’ve had it for a while now. Every since I got in the league, I’ve had it. It’s something that you’ve just got to manage as best as you can, take care of it as best as you can. Yesterday, I just kind of made it mad. Got stuck in the grass and aggravated it a little bit. I’m a little sore, but I’ll take this day and the off day and get back to practice Saturday."

With Claiborne out, the Cowboys moved Sterling Moore up to the first team and rookie Terrance Mitchell took some snaps later in the workout with the No. 1 defense. Brandon Carr has missed training camp to tend to his ailing mother, and there is no timetable for his return.

Fullback J.C. Copeland will also not practice because of a knee injury. He went down during special teams’ drills on Wednesday.