Very hard to call. There seems a lot at play here for future decisions regarding playing further if he knows he will get drafted. He likely doesn't have a college diploma that is highly regarded in the real world of jobs that require a 4 year degree, if he has one at all. Colleges like Oklahoma can keep a kid in a job if they are willing to work hard, even if it's not the NFL dream job he 's hoping for.
On another note, we've seen players come to Alabama that probably could play day 1 at a lesser University with less quality players in front of them that get to play more snaps.
Leonrard Fournette is not 100 percent. He's been rode pretty hard since his arrival at LSU. Lattimore was basically used up at USCe, but there's no way to know if he'd been healthier if he played somewhere else. At least you can only speculate. Alabama used Derrick Henry as a workhorse his last year in the stretch run. I still believe had he gone to a team with less depth at RB he would have been overworked. I don't think that happened at Alabama. Eddie Lacey didn't play much until his last year full time.
It's probably a very tough decision for this player who has most likely felt and been told he was an NFL lock. He may just now realize he's just as mortal as any player and "concussion prone" is not something you want attached to you when the NFL has been a life long aspiration.
I do think he and Oklahoma could have handled this situation much better with more discourse and planning.