I would think that this was a given. To leave would mean that he would seeking to compete with the world's best just 12 months removed from playing Junior College ball as a Sophomore in Mississippi.
He is good, Bama's coaches are good, but I don't know that they are all that good.
A second year will give him the chance to learn from coaches who know what it takes to be successful in the Pros, let him be a know-factor when is comes time for the press to select their pre season awards watch-lists, and double his exposure to those that might draft him.