When Costa will return is uncertain.
The Cowboys medical staff was swift in treating Costa by giving him the league-mandated NFL Sidelines Concussion exam, which is a battery of simple tests evaluating concentration, basic thinking skills and balance. If a player fails any of these tests, he's supposed to sit out the rest of the game.
How quickly the Cowboys treated Costa brings to mind the controversy in Cleveland with how the Browns' medical staff dealt with quarterback Colt McCoy and his apparent concussion, suffered during Thursday's game.
A main issue with Costa: The Cowboys play Saturday at Tampa Bay, and that gives him one less day of recovery time. If he can't go, Kowalski most likely will start.
"He did a good job, he stepped in," quarterback Tony Romo said. "He had a couple of things, communication stuff. He did a great job coming in not having had reps with me. I was proud of him."