I believe Alabama and their arrogance (including Saban) figured they were good enough to win without taking Clemson seriously. I think they believed a true freshman QB would have some hiccups and they could get to him. As we have already discussed on here, I think they just watched tape of Clemson from their other games this year and thought that was enough. They looked like they thought they could just show up and win. Didn't work out so well for them.