Cowboys right guard Zack Martin needed help off the field with 11:03 remaining in the fourth quarter.
He did not even head to the sideline but instead went directly into the tunnel to undergo further medical evaluation. Dr. Dan Cooper, the team doctor, was among those escorting Martin.
Martin has never missed a game in his NFL career.
He injured his knee in the first game against the Eagles but returned after a trip to the locker room.
Martin was injured Sunday while blocking on a Dak Prescott pass to Amari Cooper for a 12-yard gain.
The Cowboys list him as questionable to return with a left knee injury.
The Cowboys have taken a 16-9 lead on a 28-yard touchdown from Prescott to Cooper with 7:46 remaining.
