I've found NASCAR on a football field
Welp he won't have a "killer spring" given he is not enrolled per the recent spring roster released by Cal. I see no reason why he can't adapt his running style into Cal's offense.
If this guy has wheels we can use him in any style of offense. Musgrave will dial up some quick hitters like Dives, Bellys, Off Tackles, Whams and Traps for him. But don't rule him out on slow developing plays as well. Zone reads develop slow on purpose, so the RB can watch the blocking evolve and pick the best lane from the backside C to the frontside A gap (or whatever configuration of ZR they run). If he has quickness and speed then he can be gone as soon as a lane opens up, and if he's used to bouncing to the backside then that's typically the bailout for a ZR. Don't fool yourself into thinking this kid can't be a three down back. If he can find the holes, has the balance and toughness to attack them and the juke and speed to get through, then he'll ball out.
Good luck Ashton and we look forward to seeing that uncoachable element - speed.