he's not that great defensively. crazy aggressive, not crazy good. could be crazy good, down the road a bit (a lot of people could be, but thomas seems to really, really like defending, so it's much more likely that he will be).
i got some pushback from it when i mentioned it before, but i watched him again yesterday and it confirmed my opinion - njohnson is a very good onball defender for a freshman - at least out away from the basket. too small the closer you get.