Dallas Cowboys rookie cornerback Morris Claiborne is watching from the side again.

Claiborne, who missed offseason workouts while recovering from wrist surgery, could now miss a week or more with a sprained MCL in his left knee.

“I can’t control this, so I’m not going to beat myself up over it,” Claiborne said after watching the team’s walkthrough practice Saturday. “All I can do is go in there and do what I need to do with rehab.”

After getting hurt toward the end of practice Wednesday, Claiborne got treatment on his knee the following day, an off day for the team. He tried to practice Friday, but came off the field and later had an MRI that revealed the sprain.

Claiborne described his knee as tight and sore.

The Cowboys (No. 15 in the AP Pro32), who play their preseason opener Aug. 13 at Oakland (No. 23), drafted Claiborne with the sixth overall pick in April after trading up eight spots and giving up their second-round pick. He is expected to be a starter alongside Brandon Carr, the team’s primary free agent acquisition during the offseason.

“We don’t think it will be too long,” coach Jason Garrett said. “Morris is a smart football player. He understands things intellectually and he is able to carry the information from the meeting room to the field. He is going to stay engaged like the other guys who have been injured, stay engaged with the installation, with what is going on in terms of the coaching on the field.”

Running back Phillip Tanner has a broken bone in his right hand. Garrett said Tanner would return to Dallas to have surgery, but could be back in a week or so if that goes well.

Receiver Saalim Hakim, who like Tanner got hurt during the special teams portion of practice Friday, is also returning to Dallas to see a hand specialist about his dislocated finger.

Claiborne signed a $16.4 million, four-year contract in time to be part of three days of workouts last week at Valley Ranch for rookies and selected veterans.

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