Todd Archer ESPN Staff Writer
If the Cowboys carry a third quarterback on the roster to start the season, it wont be Dustin Vaughan, who has been informed of his release, according to a source. Vaughan spent last year on the active roster as the No. 3 behind Tony Romo and Brandon Weeden. If he clears waivers, he would likely be brought back to the practice squad. The fourth QB, Jameill Showers, will also be released.