I don't think the size of the RB is going to be the key. I think their running backs can hurt us if we have to worry about the pass. I think Bama is going to attack us similar to how we attack them. We will try to spread the field and give our guys one-on-one match up. They will do the same. They are more effective at running because teams have to worry about Cooper (and, to some extent, the other receivers). We will have to maintain our gap integrity and prevent being outmanned (actually having more blockers than tacklers).
That's my idea on the situation.