Kyrie: A-/B+ ---> has had some special games (probably responsible for an extra 4-5 wins because of clutch play) and really made an effort to fit in. Has yet to have a stretch of supernova games where he just dominates, though.
Brown: B ---> incredible improvement year-to-year. He's basically a longer, more athletic prime Jae Crowder with room to improve. His feel for the game, while much improved, still leaves something to be desired. If he gets his handle/decision making to the next level he will go from a great off-guard to a star.
Tatum: B- ---> he's doing incredibly well for a rookie; not afraid of the moment. Rebounds well. He tends to disappear for stretches/games, but he's shown up when it matters most more often than not. Let's put it this way: I'm buying a lot of this guy's rookie cards.
Horford: B/B- ---> opened the season on a tear on both ends, but regressed back to Old Dependable Al. Hopefully, he'll turn it on when the games start mattering a little more (like he did last year). He is still incredibly important, even when he's coasting, because of his passing and defensive communication. I've noticed that his defense is slipping a little bit recently, but I have no worries about it being a permanent thing.
Baynes: B- ---> like Al, Baynes started the season on a tear. Now, his midranger isn't falling 100% of the time. However, he's still a fantastic rebounder and post defender that works hard. I love having him in the starting lineup, even with his offensive limitations.
Theis: B ---> this is more based on exceeding expectations than reality, where Theis is a realistic B-/C+. He's always in the right place and plays much bigger on both O and D than he actually is. I was expecting a bench scrub, but the Celtics got a legit rotation big.
Smart: B-/C+ ---> singlehandedly won a few games for the team (Rockets, anyone?). Is still an underrated playmaker (especially on the pick and roll) and an improving scorer (I like the midrange shot he's developing). However, on the whole, Smart has not met my expectations this year, and I think he's an average-to-slightly-above-average player. Think bad starter, good bench player.
Rozier: C+/C ---> like Smart, has some good games and bad games. His highs aren't as high, though. Solid backup guard with potential to improve. For now, though, he's one step forward, one step back.
Morris: B-/C+ --- Admittedly, I haven't seen a ton of Morris minutes (haven't caught a lot of games recently in which he's played). I'm not a huge fan (he doesn't really move without the ball), but people say his offense has helped the bench more often than not. In my eyes, he's a solid role player who's being asked to perform slightly above his talent level for the time being.
Semi: C- ---> I'm honestly not a huge fan of the guy. I'm not as high on his defense as some (I think the "LeBron/Giannis stopper" moniker was not earned, and he's a but slow laterally), and his shot doesn't look like a good one to me. He is a big man, though.
Larkin: C+/C ---> good energy guy off the bench. Has won the C's a few games by getting the energy back up. The offense tends to stagnate when he's in the game for long stretches, but he's a good third PG.
Yabu: D ---> I want DLeague Yabu! NBA Yabu seems lost out there.
Nader: D- ---> see Yabu. I have to admit, I've never liked Nader's game, even in Summer League. He seems very bull-in-a-china-shop. He did bring good energy in one game I remember, though.