because his draft stock couldn't possibly get any better.

Seems logical to me. Why risk the injury and put in so much hard/dangerous work for so little pay?

I'd recommend he take the year off from football. Make a million bucks from endorsements (if he likes school then take some interesting classes - if he doesn't like school then no need to waste his time in classes he won't pay attention in anyway)- work out with personal trainers - avoid the dangerous contact to your body and go into your rookie year in the NFL in the best shape of your life.