Return...
1. He loves the offense he's in now
2. He's not projected to be that high of a draft pick
3. I don't think he's a hardship case (should still be some residuals coming in from "Me, Myself, and I" and his dad had that cameo on "Feel Good Inc." by the Gorillaz)
I also don't believe he's hard pressed for money as his father's rap career surely earned him a trust fund.
Mason would be one of the better backs in this class. He just doesn't have the measurables of an NFL player, so I'm not certain he'd be drafted high even if he did come out.
Also, if he waits until next year, he's going to be way low on the board. Gurley, Yeldon, Davis, and Hill will all be eligible for the draft and all are prototype NFL backs.