I would say: pretty good. I might be with Tommy on this but I've never seen a rookie playing defense that good. Especially post-ASG, he was beast. All deflections, steals, forced turnovers. Boxscores can't really reflect on everything he does. All this little things he's just incredible at. I find it amazing he is only 21 years and he already has instincts and timing soooo good. He plays like a veteran. In fact, he was second in the NBA (tied with Devin Harris) in offensive fouls drawn (52 overall, Kyle Lowry was first with 54). I even made a compilation with best offensive fouls/charges taken by him.
https://youtu.be/WnNT0Sy226wPer36 minutes he was averaging 2.0 steals per game - other rookies to do that last couple of years were e.g. Wade, James, Iggy, Paul, Lowry, Rondo, Curry, Wall or Rubio. What is more, last season he was 6th among all players in percentage of keeping his opponent in front, 14th in deflections and 5th in turnovers forced per chance (all stats provided
by our own Kevin O'Connor). And we are talking about rookie who is 21 years old. It's insane. He's learning so quick and month by month he is better defender, using his intellect and temper as a source of being fierce and competetive. He was progressing all season long, learning how to be more succesful, how to use his length and how to react on pump-fakes (at first, he'd commit too many fouls). He's a future all-defensive teamer for many years.
Being hard-worker can only help. I am very excited about his future with the Celtics and I think I am not the only one who says he has a chance to win DPOY some day.
What do you guys think? This is my first post here so I'll welcome any feedback.