The Dallas Cowboys had one of the worst defenses in the National Football League last year and this offseason committed to a change on that side of the ball. Change began with the swapping out of coordinators with Mike Nolan out after just one year and Dan Quinn in after being dismissed as the head coach of the Atlanta Falcons before last season even hit the midway point. Change involves more than just the staff as the Cowboys saw longtime veterans Sean Lee and Tyrone Crawford retire while choosing not to bring certain other players back.