Coach Jason Garrett left open the possibility that undrafted rookie Kevin Kowalski could start even if Costa was healthy enough to play. Costa was forced from the Giants game with a concussion in the first half and did not practice last Tuesday or Wednesday.
The Cowboys are dressing only seven offensive linemen with Jermey Parnell and Kowalski as the only reserves. Derrick Dockery is inactive for the first time in seven weeks. He had been part of the field goal team but had not taken an offensive snap.
With Mana Silva inactive, the Cowboys have only three safeties available on the gameday roster in Gerald Sensabaugh and Abram Elam and Danny McCray. Cornerback Alan Ball could be used at safety if necessary.