Updated: Dec 22, 2020
Projected Starting Lineup C: Daniel Theis - Tristan Thompson - Robert Williams PF: Jayson Tatum - Grant Williams SF: Jaylen Brown - Aaron Nesmith - Semi Ojeleye SG: Marcus Smart - Payton Pritchard PG: Kemba Walker - Jeff Teague - Carsen Edwards
Warning! I'm pessimistic! There's a lot of excitement for the big three in Boston of Tatum, Smart, and Brown, to continue to march forward as they age another year and take one step closer to that sweet nectar of winning it all, but I think a lot of people haven't particularly looked at the moves they made this off-season and how big the losses really were.
I've never been super high on Marcus Smart or Jaylen Brown. They're good, but not all-star level in my opinion. Even if Jaylen Brown makes an all-star team, I just think people don't realise how good Jayson Tatum is, and that leads the two formerly mentioned players to get a little bit over-rated. I think Tatum's comfortably a top-10 player in the league next year. He can just do everything you want from a big wing creator. Like I kind of think he's just a more consistent version of former MVP, Paul George, but without the injury problems, the drama, and a lot more youth to project for a continued improvement.
Boston "upgraded" at center by adding Tristan Thompson over the off-season, but I don't even think he's better than Daniel Theis. Not that he's going to necessarily be worse, they're just kind of the same in a best-case scenario. I don't think their center woes are banished with this signing, but I never really thought it was a huge concern to begin with, and potentially having 48 minutes of reliable center play is nice. I like Theis a lot, he was just surrounded by a lot of talented guys so he did what he needed, and not much more, so I don't think people should be too upset having him as their starting 5. Thompson was not good last year on the Cavaliers, and you can argue he simply wasn't engaged because he was playing for Cleveland, but looking at on/off numbers he was the worst of Cleveland's starters despite having a lot of good candidates for "worst starter on an NBA team" playing alongside him. Being relieved by John Henson and a frisky Larry Nance/Kevin Love frontcourt duo don't really justify why he would have such a bad net rating without just kinda being bad. Celtics' next biggest signing was Jeff Teague, who enters the season coming in at 32.5 years old, as the replacement for Brad Wanamaker, who left in the off-season. Teague comes off an unimpressive split season in 2020 with the Timberwolves, and eventually Atlanta, who he was traded to in a package with Treveon Graham for Allen Crabbe, not exactly the biggest names. I don't think he's terrible as a creator, but comparing his defence to the point guards he shared minutes with last year while on the respective teams, Shabazz Napier was 6 whole points better than Teague on the Timberwolves, and even the man dubbed the worst defender in the NBA, Trae Young, was 1.6 points better defensively than Teague in his limited, but not completely unsubstantial 336 minutes with the Hawks with Trae off the court. So we'll see how Celtics fans feel about that part of his game once they're forced to actually perceive him.
The bigger, more pressing loss was that of the 120 million dollar man, Gordon Hayward, who had a bit of a tumultuous time in Boston with injuries and a reduced role, but he was still really important to them. Via on/off numbers he was the Celtics third best player last year (Kanter was #2, also left in the off-season). In lineups with Tatum and Hayward together they were +10.98, and -7.04 with both of them off. Now, a lot of that is on Tatum as he was the third most impactful player all-season in the NBA behind Giannis and LeBron, top 2 in MVP voting, but Celtics were only -0.52 when Tatum was off in general, so that's about a 7 point impact Hayward provided in non-Tatum minutes. That's going to patched up with a rookie 3-and-D guy. I don't hate Nesmith, but he's a spot-up shooter with good athleticism that can't really shoot off the dribble well enough to put himself amongst the likes of a Duncan Robinson or JJ Redick that some people might think he can be. He's got a lot of attention for hitting 52% on 8 attempts a game beyond the arc in half a college season against non-conference opponents, but he was also .337 in college the year before on a full season. His FG% is actually worse than his 3P% which is a pretty rare stat, but he forces bad rim attempts with his tunnel vision and doesn't really see any passes except simple dump-offs when driving, or he's taking those off-the-dribble jumpshots I mentioned earlier at an unimpressive conversion rate. He is a solid defender though, I do think he can be a positive. I kind of like him as the 5th starter while Kemba is out, actually. I'm not really sure how good Payton Pritchard or Carsen Edwards are, but I don't expect them to move the needle, and Romeo Langford is out for at least a month. They're super shallow at guard, and the only other rotation guys on their roster are Robert and Grant Williams, who are fine but more just hustle guys. Kemba will be out at least a couple weeks to start the season and I could see it being a pretty catastrophic stretch for Boston, as Tatum is their only reliable initiator in the mean time. They also lost Kanter who I mentioned was their 2nd best player using on-off numbers, but that's of course a little inflated. He was specifically picked for lineups he would do well in, and has his defensive exploitability, but still, that was 1000 minutes he gave them over the season and playoffs of carving up teams that couldn't guard him, so it isn't completely a hand-wavable loss. I think he's as much of a loss as Thompson is an addition, but at least Thompson allows the Celtics to play the same way they do with Theis on the floor.
Honestly, I just feel like they had a really bad off-season and it isn't getting talked about enough. Hayward, who was underrated as a secondary playmaker, leaves for a trade exception, which could potentially materialize in to something good and is replaced by Aaron Nesmith. Kanter, over-inflated as his numbers might be, was still a positive and is replaced by someone who was a negative on a much worse team last year. Wanamaker, who is a solid guard defender and a reliable bench PG is replaced by a really, really bad defensive PG who is just okay at running an offence, and to go with all that, their starting PG is out for the first bit of the season.
Now, that said, I think Kemba can prove he was better than he showed last year once he's healthy, and I love Tatum, and I could see them with homecourt advantage in the playoffs, but I realistically see them as either the 5th or 6th seed depending on how they do without Kemba, and even possibly the 7th seed if things go poorly. I don't personally think they're contenders at all with the roster as-is, and I could see their bench, with Tatum and Kemba off the court, blowing a lot of leads.