Kevin Kowalski may start for Cowboys

IRVING, Texas -- Dallas Cowboys center Phil Costa has not had any postgame symptoms after suffering a concussion, but even if he's cleared, it is not a given he will start Saturday at Tampa Bay.

While Costa returned to practice Thursday, coach Jason Garrett said undrafted rookie Kevin Kowalski could start. Kowalski has impressed the coaches with his work this season and played well after Costa left Sunday's game against the New York Giants.

Costa has started the first 14 games of the season. He did not take part in practice Tuesday and Wednesday as he went through the different steps set by the league to return to the field following a concussion.

"He is on schedule to be able to play if he responds well over the next couple of days," Garrett said.

In other news, outside linebacker DeMarcus Ware returned to practice Thursday at Valley Ranch after sitting out Wednesday because of a neck stinger.

The final practice before Saturday's game at Tampa Bay started with light rain, thunder and flashes of lightning, marking the second consecutive day the Cowboys will have practiced in bad weather. They practiced in a steady rain Wednesday.

Among the missing from Thursday's session: Andre Holmes (hamstring), Danny McCray (ankle) and Josh Brent (knee).

McCray could be a game-time decision, just as he was last week. He eventually played. Holmes and Brent are not expected to play Saturday night.

Todd Archer and Calvin Watkins cover the Cowboys for ESPNDallas.com.