Is this the end of Phil Costa?

IRVING, Texas -- Phil Costa was the Cowboys' starting center to begin 2012, but back problems and an ankle injury forced him to miss nine games last season. The Cowboys started three different centers -- Costa, Ryan Cook and Mackenzy Bernadeau -- in 2012.

The interior of the offensive line was an issue last season and it prompted the Cowboys to draft Wisconsin center Travis Frederick with the 31st pick of the first round Thursday night.

Does this mean the end for Costa and Cook?

"I think they're all competing," team executive vice president Stephen Jones said Thursday night. "Frederick can be a guard. We're gonna put our five best guys on the field. I think what it means, everybody expected us to improve ourselves in the interior of the offensive line and it's going to be a battle there for everybody. But I think we're going to put our five best guys (there). If Costa wins the starting center job and if we think he's one of the best five, we might play Frederick at guard."

The first round of the draft saw three offensive tackles go in the top five and five more offensive linemen go after that. Jones said the number of offensive linemen picked in the first round had no bearing on the trade the Cowboys made with San Francisco to move down, or their selection.

"We had a handful of players we would have taken at 18," Jones said. "If they had been there, we would have taken them. When they weren't there, we felt like our best value for our team, long term, to improve ourselves, was to move the pick when we had the opportunity."