Cowboys' Phil Costa diagnosed with sprained ankle

Phil Costa's injury-plagued season just took its ugliest turn.

The Dallas Cowboys center was carted off the field in Sunday's win against the Carolina Panthers with what appeared to be a serious right ankle injury. The Cowboys announced that Costa is out and will not return.

Costa was taken down by a chop block during a fumble-recovery runback by linebacker Luke Kuechly. The Charlotte Observer reported that Panthers coach Ron Rivera ran on the field to alert game officials and the Cowboys' sideline.

Costa remained on the field for several minutes before being carted off with an air cast on his right leg. If his season is over -- a strong and unfortunate possibility -- the Cowboys' center job will go to Ryan Cook.

UPDATE: Costa has been diagnosed with a sprained ankle and could be available for next Sunday's matchup against the New York Giants, according to the Fort Worth Star-Telegram.