Getty Dallas Cowboys head coach Brian Schottenheimer. The stakes are clear when it comes to the battle to become the backup quarterback behind Dallas Cowboys superstar Dak Prescott — now the rules of the competition seem to be coming into focus as well. Cowboys head coach Brian Schottenheimer laid down some parameters for the competition between Joe Milton and Sam Howell to be Prescott’s backup. “Brian Schottenheimer said the No. 2 qb reps will be split evenly between Joe Milton and Sam Howell,”