The anatomy of a Celtics loss

Breaking down how Boston loses games, and whether they can do anything about it (or already have).

Regular season losses don’t mean all that much, until you start getting a lot of them. Then it’s bad, but after a lot more, it starts to become good again. The NBA is strange.

For the Cs’ purposes, though, losing is disappointing, but not all that relevant. Despite their current 7-6 slump, the Celtics should still cruise to mid-50s wins and a top-3 seed in the East.

What is important about losing is learning from how it happened and adjusting accordingly, like when I have a footrace with my 3.5-year-old kid. He learns that I’m bigger, faster, and stronger than him, and that I always will be (please allow me this delusion, because aging is hard).

Every NBA game is a wealth of data points, and how the Celtics use them will be paramount in their task to repeat. The NBA Playoffs are ultimately about mitigating weaknesses more than it’s about relying on your strengths, and there’s no better stage for weaknesses than a loss.

So, let’s take a look at what happens when the Celtics do stumble and whether they can do anything to avoid it, or if they already have. First up, the unavoidable:

Shooting variance losses

I’ll be honest. There’s just not a whole lot to glean from a shooting variance loss. They happen to everyone. They are inevitable, like an ice cream headache for someone with minimal self-control (someone like me). Nonetheless, here they are.

1/5/24 Oklahoma City – This loss is the freshest in my mind and I know many rushed to crown OKC as the kings of the NBA when they took down the Celtics without Chet Holmgren or Alex Caruso. Was OKC’s defense excellent? Yes. Did it make the Cs uncomfortable? Yes. Was their defense the reason the Celtics shot 3/20 on wide open 3s (no defender within 6 feet) and 8/39 on wide open and open (defender within 4-6 feet) 3s? Unless they are piloting some new ball control tech in OKC, then no, no it didn’t.

OKC, on the flip side, shot 42% on a healthy volume and it still was a pretty close game until the last few minutes. I pose one question, flip that shot variance and how much do the Cs win by? 25? 30? 40? Yes, this is a coping mechanism, but I’m fine, I promise. I PROMISE OK?

12/23/24 Orlando – Classic game of being punished by the basketball gods. Celtics let the undermanned Magic hang in for a long time and then they just kept making shots. The Cs shot a hearty 24.2% from 3, while Orlando made 39.4% despite missing all of their good players.

12/7/24 Memphis – Frustrating game. Ja Morant went 4/6 from 3 despite shooting around 30% for the season entering that game. He’s now hit the dizzying heights of 31%. Memphis shot 45.5% as a team while the Cs shot a Morant-esque 30% even. My memories of this game are of Jaren Jackson Jr. carving up any big in front of him, but really it came down to the shooting disparity.

Again, looking at those games, not a ton to takeaway in my opinion. Sometimes Ja Morant is going to hit a few threes he normally wouldn’t. Sometimes 3 of your best players won’t score in the second half. Your favorite anomaly’s favorite anomaly.

Losing on the margins

By lose on the margins, what I’m really saying is whether the Celtics won or lost the possession battle. How do you create extra possessions? Turnovers and offensive rebounds. I also put less stock in games the Celtics lose on the margins during the regular season than other losses outside of shooting variance. When the Cs are engaged and firing like in the playoffs, they rarely lose on the margins to such a degree that it costs them a game.

With that said, I find losing the turnover battle to be more informative in the regular season than losing the rebounding battle. This version of the Cs has historically been a good to great defensive rebounding team and middle of the road offensively. Turnovers, on the other hand, we have seen bite the Cs in a playoff setting.

1/10/25 Sacramento – The Kings rebounded 38.8% of their misses in the half court (per Cleaning the Glass). It probably won’t surprise you that number falls into the 90th percentile. This issue is compounded by the fact the Cs had one of their worst offensive rebounding games of the season, grabbing 22.2% of their misses in the half court (24th percentile). Yikes. The Celtics also lost the turnover battle, 12.1% TOV% to 15.3% TOV%. The result? The Kings took 102 FGAs to the Cs’ 84.

11/12/24 Atlanta – The possession-pocalypse. Atlanta turned the Celtics over 20 times and had 19 offensive rebounds. Although the Cs did turn Atlanta over 19 times, the Hawks took 97 shots to the Celtics’ 75. Not a great way to win a basketball game.

Here’s the good news, there’s only two games you can blame the margins for. Do I still randomly check for my wallet afraid that Dyson Daniels has stolen it? Yes. Do I still look over my shoulder afraid Domantas Sabonis is going to come flying over my back? Yes, but when it comes to do or die games in the playoffs, I’m extremely skeptical they will allow themselves to lose like this. The Celtics are a very low turnover team and solid on both ends of the glass. Their only real weakness is forcing turnovers, and they are trending in the right direction with that (18th in the league in the last 10 games). The Cs are very good on the margins, and they’ve continued to be throughout this somewhat disappointing stretch.

The ball pressure and rim protection frustrations

This one can be worrying, although some of it is effort-based. Teams tend to slack on ball pressure in the regular season except when things come down the stretch, but there’s a line. The Celtics have flown past that line a few times this year into sheer laziness. When the outer crust of your defense gets blown by, it puts bigs in a very difficult position. They are forced to time their help and make a play on the ball handler. All the while the backside defense must shift to cover the helping bigs’ man. The Celtics were not very good at this for a while.

10/30/24 Indiana – Allowed Indy to shoot 37% of their shots at the rim (73rd percentile) and 26% in short mid (76th percentile). Forcing teams into the short mid-range is usually a win, but not really against Indy. They are 5th in the league in accuracy from that range (although shot under their average this game). Indy generated 62 points in the paint in this game.

11/6/24 Golden State – This one is less about accuracy and more about volume. The Celtics held the Warriors to 64.7% at the rim (42nd percentile) and 21.1% in short mid-range (4th percentile). The problem is that an insane 39% (81st percentile) of the Warriors shots were at the rim, and 59% were at the rim or short-mid. They took 34 shots at the rim to the Celtics’ 17. Golden State scored 52 or their 118 points at the rim.

12/25/24 Philadelphia – It pains me to write this section, please know that. This is the inverse of Golden State, we kept Philly away from the rim fairly well, but when they arrived there, they didn’t miss. While they only shot 17 shots there, they made 14 of them. While there was definitely some shooting variance with this game, a lot of it was due to Maxey getting downhill and spraying out to shooters.

12/29/24 Indiana – Indy shot 32% of their shots at the rim (52nd percentile) and 30% in short mid-range (88th percentile). They shot 70.4% (62nd percentile) and 52% (75th percentile) in those areas respectively. 66 points in the paint. This was a horrible defensive performance, but it might have been a good thing.

I say that because since the second Indy game, the Celtics have altered their defensive approach. They’re no longer leaving their bigs on an island to corral ball handlers and protect the rim. They’ve started sending help earlier, and it’s working. Here’s an example of Pritchard peel switching with Holiday.

It’s a great way to limit straight line drives and help out your bigs. If you do it quickly enough, it doesn’t concede much of an advantage either. Sacramento doesn’t score on the play above because of the peel switch, they score because JB needlessly gambled.

The proof is in the pudding to borrow a euphemism from my great grandfather, who I never met but imagine said things like that.

If you update that number with the Pelicans game, it doesn’t change. The Cs can definitely blame a few losses on rim defense, and you could make an argument for the Memphis game to fall in this category as well, but Mazzulla has done what great coaches do. He fixed it.

Poor offensive approach

This is the only one that gives me some measure of concern. I want to be clear that it is a pretty small measure. I’m not concerned about this team’s offense long-term, but it’s been frustrating to watch at times. The offense has lost a bit of that mismatch hunting knife’s edge it had last season and still has at times this year. There are probably a few games you could put under this category that I didn’t, like OKC, but in those games the shooting disparity was so wide, that I felt it superseded an imperfect offensive approach. There are also several close wins that may not have been so close if the Cs were crisper on the offensive end.

The games below all have something in common: they are all teams that the Celtics absolutely should not struggle against offensively. Cleveland has the best defense of the bunch (8th per Cleaning the Glass) but has several juicy matchups for the Celtics to attack. Chicago (23rd) is downright bad.

12/19/24 Chicago – The Cs shot 39.2% against the 23rd ranked defense. 55.3% of their field goals were assisted, which is not an abomination, but it’s below average. 47% of their shots were above the break threes, good for 99th percentile.

12/1/24 Cleveland – A measly 44.7% of their made field goals, and there weren’t a lot of them, were assisted. Only 21% of their shots were at the rim (11th percentile), and an uncharacteristic 13% from long mid-range (90th percentile). While the Celtics didn’t shoot horribly from 3, 34.7%, they shot 40% overall. In the Cs’ defense, they were missing Jaylen Brown and Derrick White.

I think the Celtics are still working out the kinks offensively, and shooting variance is absolutely making things look worse than they really are. Going through this exercise, I expected there to be more commonality between the Celtics’ losses, and there really isn’t. They’ve lost in a variety of ways, but the most common way they’ve lost is straight up missing open shots.

Perhaps the most telling stat I found isn’t one that highlights their losses but highlights their wings. When the Celtics assist on 65% or more of their made field goals, they are 14-1. It’s the wrong approach to evaluate this minor rough patch from the angle of “what can they do to stop losing.” We should be looking at it from the perspective of “what does this team do when it wins,” and share the ball and limit rim attempts are two of the mainstays. While the Celtics’ December was rocky, they are also all of the sudden 5-2 in their last seven. And we know come the Playoffs, I don’t think I’ll have all that many examples for any of these categories.