Again, just so we can keep things straight, Kyle Shanahan is hardy a run-option specialist and pretty much zero chance he would bring that here. He's from the West Coast Offensive family via Mike Shanahan and Gary Kubiak. He brought elements of the read option to DC only because they drafted Griffin. Also, it seems pretty clear that the front offense wants a philosophy shift away from the Coryell on offense. they've been looking to implement zone blocking since 2011, and brought in Castillo in to fully implement it, they didn't bring in Castillo in for the heck of it and let him run any scene he wanted...just like they're not looking for an OC just to fit Castillo's scheme. Rather they want someone to fit the organization's new philosophy, of which Castillo is a part. Turner has the same basic philosophy as the one we're moving away from. He's not a match with the shift, therefore it wouldn't make much sense to bring him in.