Other than the year of the Polish Rifle, I don't know of an era with less QB depth than what Mullen usually runs with.
We had Ralph/Russell/nobody
We've got Russell/injured Dak/nobody.
I've never seen a coach as content to have 1 to 0 QBs behind the starter.
Maybe I'm overstating that Mullen is content with that. He just can't build QB depth for shit.

