It makes more sense for Fous to play most, if not all, of his minutes at the 5. But I'm guessing Fous realizes he'll be a lot more successful post graduation if he's a reasonable sized 4 rather than an undersized 5.
No idea if he'll be successful making that transition or even if KY will let him (depends somewhat on the last roster spot I'm guessing), but I've heard that's Fous' goal.