Winning the margins: who drives the Boston Celtics’ possession edge?

Joe Mazzulla usually talks about his willingness to “dominate the margins and dominate the possessions.” However how?

The general public usually focuses on offensive rebounding when speaking in regards to the possessions battle. But, there are three different levers to this battle: defensive rebounding, forcing turnovers, and caring for the ball. As a result of this possession battle appears to develop into an increasing number of necessary, why not have a look at who’s one of the best at it? Who has essentially the most affect on the possession battle on a basketball courtroom?

This concept got here after studying Owen Phillips’ glorious piece on the “Turnover Economic system.” I needed to dig deeper. What if we checked out this query from a extra particular person perspective—and included each turnovers and rebounding?

Utilizing 2024–25 on/off knowledge from Cleansing the Glass, I attempted to estimate how gamers influence the variety of possessions their groups acquire or lose—each on offense and protection—after they’re on the courtroom.

To take action, we want key metrics:

OFF POSS ADD (offensive possessions added) = (ORB% × 0.533) – TOV%

This tries to estimate what number of further possessions a participant creates on offense, by grabbing offensive rebounds and limiting turnovers. The 0.533 issue comes from this season’s common miss charge—so it scales offensive rebounds to precise further shot alternatives.

DEF POSS ADD (defensive possessions added) = Compelled TOV% – (Opp ORB% × 0.533)

This estimates what number of further defensive possessions a participant’s workforce positive aspects because of their capacity to drive turnovers and safe the rebound after a missed shot.

TOT POSS ADD (whole possessions added) = OFF POSS ADD + DEF POSS ADD

That’s the sum of each, giving a tough thought of how a participant shifts the possession steadiness per 100 possessions performed.

The rationale we’re utilizing on/off knowledge is to keep away from the bias of focusing solely on particular person efficiency and relatively have a look at the affect a participant has on workforce efficiency. An awesome instance of why particular person rebounding metrics are biased is Andre Drummond. Regardless of being seen as the most effective rebounders of all time, his groups had been typically higher at rebounding when he was off the courtroom.

The possession battle is a collective effort, and that’s why on/off statistics give us a greater sense of particular person affect. But word that on/off additionally has its personal biases—similar to who’s on the courtroom with the participant or who his backup is. No metric is ideal, however let’s dive into the numbers and attempt to perceive who’s one of the best Celtic at including possessions on offense and protection.

A two manner avenue

Whereas some groups, just like the Houston Rockets, try to win the possession battle from the soar until the tip of the sport, the Celtics appear to have one other strategy. Trying on the knowledge, the Celtics seem cut up into two totally different groups.

Within the backside left, yow will discover all of the starters. The gamers in that a part of the chart are those much less more likely to have helped the workforce win the possession battle this season. On the opposite facet of the road that cuts the chart in two, yow will discover all of the gamers from the bench who performed greater than 300 minutes.

Watching the video games, there was a transparent feeling that with Luke Kornet and Payton Pritchard on the ground, the Celtics had been crashing the offensive glass much more. However this two-way strategy to the possession battle goes past that. On each offense and protection—by rebounding and turnovers—the Celtics had been extra intentional about successful the possessions battle with the bench unit than with the beginning 5. Why?

Profitable the possession battle usually comes from groups who lack offensive firepower or capturing, just like the Houston Rockets. Due to this fact, it is sensible that the Celtics’ bench confirmed extra willingness to combat and create extra possessions to compensate for the extra expert gamers resting. However the offensive construction of the beginning 5 additionally had an affect.

Certainly, essentially the most influential gamers within the possession battle are sometimes facilities. Their measurement impacts rebounding, and the bottom they will cowl influences the power to generate turnovers. Due to this fact, with Kristaps Porzingis spending most of his time on offense past the three-point line, it is sensible that the Celtics’ beginning 5 is much less more likely to generate further offensive possessions. Nonetheless, what’s extra attention-grabbing—and will have foreshadowed the Celtics’ struggles in opposition to the Knicks—is the beginning 5 underperforming on protection by way of producing further possessions in comparison with the bench.

It’s no secret that the Celtics misplaced in opposition to the Knicks partly because of their incapability to guard the glass and their struggles within the margins. Nonetheless, over the course of a full season, are the Celtics who assist win the possession battle additionally those who assist win video games? Properly—sure and no.

Is successful the possession sufficient?

For many who learn loads of my 10 takeaways and tactical deep dives, it received’t be breaking information that the Celtics had been at their greatest with Kornet on the courtroom. As we see on the chart under, the Celtics’ backup large man was on the ground when Joe Mazzulla’s workforce was successful the margins—and the scoring differential.

Additionally, some gamers had been nonetheless extremely optimistic regardless of not performing notably properly within the possession battle—similar to Derrick White or Jayson Tatum. There have been additionally gamers who helped the workforce dominate the possession battle however weren’t as impactful on internet score, like Pritchard or Neemias Queta. After which, there are three gamers who underperformed in each: Porzingis, Jrue Vacation, and Jaylen Brown. Over the course of the season, the Celtics had been extra more likely to win the possession battle and have a greater internet score when these three had been on the bench.

Total, this reveals that the Celtics had been in a position to play two kinds of basketball: the five-out spacing with the starters, and the gritty possession battle with the bench. And whenever you combine all of it, you find yourself with a fantastic common season. This additionally demonstrates that successful the possession battle is necessary—however not at all times sufficient to win. Additionally, word {that a} participant’s influence on the possession battle relies upon closely on context and function optimization. As we speak, Kornet is likely one of the greatest gamers at serving to his workforce win that battle. Earlier in his profession, in a special context with totally different assignments, he was one of many least impactful gamers on that finish.

If you wish to learn extra in regards to the possession battle throughout the NBA, be at liberty to take a look at my current Twitter thread on the subject: