They were running the ball very well in the beginning of the game. They were taking chunks out of Clemson's defense.
My personal opinion is that their OC panicked when Clemson got up by a couple scores. They abandoned the downhill running game.
Bama actually was doing a great job running the ball. (at least in the 1st half)
They went away from it, probably because they tried to keep up with Clemson's scoring.