An outside the box thought. Perhaps Daboll isn't planning on calling the plays.
While it's commonplace for a new HC to hold onto playcalling duties, some forgo it to concentrate on running game management. Also, Daboll may not want to call plays from the sideline. If memory serves correct he attempted that early in his Buffalo career before heading upstairs. Possibly, he believes that is optimal for the playcaller and may lead to him offering a guy he knows, respect and trusts (Dorsey) a shot a calling the plays.