The tropes of playoff success are driven into the psyche of every NBA fan ad nauseum by very handsome podcasters and blog boys alike. You know them and can probably recite them before I do.
The game slows down.
You have to take care of the ball.
The refs swallow their whistles.
There are certainly others, but I imagine all fans can agree that these are the big ones and with that in mind, I went out to my massive Twitter following and posed this question:
I think half-court ORTG and DRTG. This adds up to kind of the half-court net rating. I believe those translate well.— Guilherme Theis (@GuilhermeTheis) April 2, 2023
If you look at this season you’d have Sacramento to be the best and honestly nobody is fearing Sacramento specifically due to their Defense
I received an overwhelming response. Yes, there was only one response, but the content was overwhelmingly helpful. When you take these stats and reflect back on the common playoff tropes above, you start to see a correlation which finally brings us to what this article is about. Is there a way to use stats to evaluate whether the Celtics satisfy the common tropes of playoff success? I hope so. Otherwise, I’m wasting a lot of my own time and yours.
“The game slows down.”
Relevant Stats: Halfcourt ORTG, Halfcourt DRTG, Offensive and Defensive PPP in isolation
When someone utters the phrase “the game slows down,” what they are really saying is that the easy baskets many teams feed off of in transition are simply less frequent in a playoff setting. Offenses are more careful, they clean up the silly mistakes, and they are less aggressive attacking the offensive glass. All this adds up to playoff games, especially during crunch time, being played at a slower pace and in the halfcourt. It also means that as offenses try to limit mistakes, they run less complicated stuff and end up getting into isolation possessions more often.
So, in order to evaluate how the Celtics might stack up in a slower paced environment, we are going to look at two sets of data: how they fare in the halfcourt on both ends, and then how they fare in isolation.
First, the good news. The Celtics are monsters in the halfcourt. Per the geniuses at Cleaning the Glass (who filter out garbage time in their stats), the Cs have the 3rd best halfcourt offensive rating in the league at 103.4 points per 100 possessions (that’s if you filter out putbacks; if you don’t, they are still 3rd at 118.3, but for the purposes of this discussion I’ll be focusing solely on the numbers where putbacks filtered out).
The team leading the league in halfcourt ORTG got Kyrie’d and isn’t even going to make the playoffs (sorry, Mavs fans). Second is Sacramento with their historically good offense and a team the Celtics are very unlikely to see in the playoffs. To put it in terms even I can understand, the Celtics are really, really good at scoring in the halfcourt.
Second, some less good news, but still good. The Celtics’ halfcourt defensive rating is a solid 97.5. That’s good for 10th (we will get to their ranking including putbacks in our next section). There’s almost certainly some noise here leftover from the early season where the Celtics torrid shooting covered up a below average defense. Per NBA.com’s less specific DRTG stat, the Cs have the best defensive rating in the league since January 1st. In other words, I suspect the Celtics are a bit better defending their own half than this number shows. So far, so good.
Third, some kinda ok, some kinda not good news. When the game slows down and offenses get less creative, you have to be able to score in isolation. The Celtics are pretty mediocre at that. That’s not exactly fair; that implies there’s some doubt to how mediocre they are.
They are the definition of mediocre at scoring in isolation as they rank exactly 15th in points per possession. I assumed this was likely due to one player bogging down the team’s overall average, and Smart’s 25th percentile on a single iso possession a game certainly doesn’t help, it actually turns out their 3 most common iso players are also profoundly mediocre as well. Malcolm Brogdon, Jaylen Brown, and Jayson Tatum all rank between the 52nd (Brown) and 60th (Brogdon) percentile in points per possession. The upside is that having three guys that are pretty good to decent in iso means that one of them will be able to attack a weak defender (Jrue Holiday can’t guard them all!), so there is an argument that they’ll be a bit better come playoff time.
Finally, some bad news. I won’t dwell on it because I find NBA.com’s defensive play type data to be wonky and inaccurate and because it makes the Celtics look bad. The Celtics are 23rd in defensive iso points per possession. They’re getting crushed when teams iso them, which is inexcusable given all of the defensive talent on this team. The hope is that these issues are mostly effort based and, thus, are merely a regular season problem.
Trope compliance: B+
“You have to take care of the ball.”
Relevant stats: Turnover % and Defensive Rebounding %
When I hear “we have to take care of the ball” regarding the playoffs, I immediately think turnovers, and that’s certainly a large part of it. But as I began to think, and the out of shape hamster that operates my cerebral cortex began to run, I realized there’s another aspect of this: ending defensive possessions. If a team is lazy on the defensive glass and gives up offensive boards, they aren’t valuing possession, and that’s at the very essence of taking care of the ball. Hence, we are going to look at the Celtics’ turnover percentage and their defensive rebounding percentage in this section.
Ahh, turnovers, our cruel mistress from last offseason. The proverbial Snorlax blocking our path to a championship. I have flashbacks to Tatum and Brown driving right into Draymond Green’s help as three Warriors swipe down on the ball and sprint the other direction. Are we in for another frustrating turnover wrought post-season, or have we found our pokeflute and the path is clear?
I can definitively say that I’m not sure. The upside is that the Celtics rank a very solid 7th in turnover percentage, so they take care of the ball considerably better than most of the league. Last year they were 13th. While that sounds great, the gaps here are paper thin. Last year’s percentage was 13.9% and this year’s 13.3%. Not a huge difference, but playoff games are won on the margins, and even a slight improvement can turn a close game your way. Perhaps the steady hand of Malcolm Brogdon and the increased comfortability of Derrick White can make sure the improvement translates to the playoffs.
Nonetheless, one place where the Celtics truly excel at taking care of the ball is the defensive glass. They’re first in defensive rebound percentage in the league. Nobody ends defensive possessions better than the Celtics. Remember that halfcourt defensive rating above? Well, if you include putbacks into the calculous, the Celtics jump from the 10th best halfcourt defense to the 4th. That’s more like it. With Robert Williams getting healthier and likely playing a bigger load in the playoffs, I don’t see any reason it can’t stay that way.
Trope compliance: A-
“The refs swallow their whistles.”
Relevant stat: percentage of points from free throws
You’re never going to believe this, but the Sixers lead the league in the percentage of their points that come from the line. Shocking, I know. The Pistons are second, which actually is shocking.
If any trope is true about the playoffs, it’s probably this one, unless you’re Giannis Antetokounmpo. Actually, if you’re Giannis, they do swallow the whistle, it’s just to ignore the 13th offensive foul you committed that quarter.
Regardless, as we know, the Celtics shoot a lot of threes. It probably comes as no surprise then that very little of their offense comes from free throws. They rank 26th in percentage of points from the line. That’s a bit of a double-edged sword, kind of like Giannis’s elbows, as it means they probably aren’t getting to the rim as much as other teams. The Cs rank 15th in drives per game, so there’s some legs to that argument. That said, the Celtics’ offense very much leaves their fate in their own hands: they either make shots or they don’t. There’s no requirement that the refs actually call fouls when they should.
The one hangup? Jayson Tatum. He’s the only guy that gets a significant amount of his points from the line, a shade under 24% (Derrick White is second at 16.6%). Are we worried Tatum’s slightly below average 3-point shooting will be compounded by an inability to get to the line in the playoffs? I’m not, in large part to his improved finishing through contact. It’s still certainly something to track, and it’s not like it’s impossible to get to the line in the playoffs. Just ask Giannis.
Trope Compliance: A-
Like most things, tropes are imperfect. But there’s truth to them, even if overstated at times. If you look at the common tropes about the playoffs, the Celtics sure look like the best team in basketball. If you look at all the other ways we analyze basketball, like net rating or record or watching games; well, the Celtics sure look the best team in basketball there to. Now, all they have to do is go out and prove it.