IRVING, Texas – Center Ryan Cook is not practicing Wednesday because of a sore knee, which has caused the Cowboys to reconfigure the offensive line yet again.

Mackenzy Bernadeau is taking the first-team snaps at center and veteran Derrick Dockery is at right guard. Phil Costa has missed the last three games with a dislocated ankle and will need a few more weeks before he can return. Kevin Kowalski is in his second week of practice this season after spending the first nine weeks on the physically unable to perform list.

Running back DeMarco Murray (foot) was on the field in a helmet and cleats, but he will continue his rehab. Cornerback Mike Jenkins will miss his third straight day of practice because of a back injury. He did not play last week at Philadelphia.

As the portion of practice open to the media was closing, linebacker DeMarcus Ware went with a group of players rehabbing. His hands were taped and he was in shells, which is a sign he will practice in some fashion. He was not on the injury report last week.

Defensive end Sean Lissemore (ankle) and safety Matt Johnson (hamstring) also are not practicing.

The Cowboys added two practice squad players in linebacker Jerry Franklin and defensive end Tevita Finau with the recent call-ups of Vince Agnew and Ben Bass.