Injury issues. Made the correct decision. Keeps getting hurt and might not get drafted. He will be just fine.
This is the reason I think he should have stayed. I think GMs will be very skittish to draft Dortch given his injury issues even with his upside. If he would have stayed a year and remained relatively injury free and put up gaudy stats as he would have, I would think that could have bought him a couple of rounds bump to see he can handle the rigors of a full season while producing more dazzling highlights.
And the diff. in a couple of rounds in guaranteed and total contract values is large.