I remember that at the time of the draft that one of the reasons given for his poor outside shooting was the unusual size of his hands.
Definitely sounds legit.
Last season, I started practicing holding the ball in one hand, away from the opponent. It helps me a lot since I'm a guard, and I can now do some moves while holding the ball in one hand. It also helped me on layups and when going to the rim, because I have a lot more control on mid-air fakes and spin/direction and I get more use out of my wrist.
However, it totally wrecked my shot, as I started gripping the ball tight and throwing it more like you'd throw a baseball instead of rolling it off my hand.
Sounds like that's somewhat the same issue.