Saban put him through the wringer and came out convinced that Marcus can grow up and contribute. You can't deny this guy's athletic ability - and again, that's what its all about at this point.
However, I'm starting to think Saban is a little overconfident in his ability to deal with malcontents. I think after dealing with Culpepper for a while, he'll be happy that he doesn't have Ricky around at the same time. God help him if Culpepper and Marcus start hanging out together.