If you go by DRPM, he was roughly neutral on defense. So compared to his poor offense, defense was where he stood out.
I'm not saying he was a great defensive player, but I think he did pretty well, all things considered. He has a lot to improve though to even be an ok starter.
He was also the top PG for staying in front of his assigned player. With his length this is the best thing you can ask of a perimeter defender.