Successful the margins: who drives Boston’s 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 concerning 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 grow to be an increasing number of vital, why not take a look at who’s the very best at it? Who has probably the most affect on the possession battle on a basketball court docket?

This concept got here after studying Owen Phillips’ wonderful 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 achieve or lose—each on offense and protection—once they’re on the court docket.

To take action, we’d like key metrics:

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

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

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

This estimates what number of additional defensive possessions a participant’s crew features because of their skill to power 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 concept of how a participant shifts the possession stability per 100 possessions performed.

The explanation we’re utilizing on/off knowledge is to keep away from the bias of focusing solely on particular person efficiency and fairly take a look at the affect a participant has on crew efficiency. An ideal instance of why particular person rebounding metrics are biased is Andre Drummond. Regardless of being seen as top-of-the-line rebounders of all time, his groups have been typically higher at rebounding when he was off the court docket.

The possession battle is a collective effort, and that’s why on/off statistics give us a greater sense of particular person affect. But be aware that on/off additionally has its personal biases—reminiscent of who’s on the court docket 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 the very best Celtic at including possessions on offense and protection.

A two method avenue

Whereas some groups, just like the Houston Rockets, are attempting to win the possession battle from the soar until the top of the sport, the Celtics appear to have one other strategy. Wanting on the knowledge, the Celtics seem cut up into two completely different groups.

Within the backside left, you’ll find all of the starters. The gamers in that a part of the chart are those much less more likely to have helped the crew win the possession battle this season. On the opposite facet of the road that cuts the chart in two, you’ll find 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 have 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 have been extra intentional about successful the possessions battle with the bench unit than with the beginning 5. Why?

Successful the possession battle usually comes from groups who lack offensive firepower or taking pictures, just like the Houston Rockets. Due to this fact, it is smart that the Celtics’ bench confirmed extra willingness to battle 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, probably the most influential gamers within the possession battle are sometimes facilities. Their measurement impacts rebounding, and the bottom they’ll 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 smart that the Celtics’ beginning 5 is much less more likely to generate additional offensive possessions. Nevertheless, what’s extra fascinating—and will have foreshadowed the Celtics’ struggles in opposition to the Knicks—is the beginning 5 underperforming on protection by way of producing additional possessions in comparison with the bench.

It’s no secret that the Celtics misplaced in opposition to the Knicks partially as a consequence 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? Nicely—sure and no.

Is successful the possession sufficient?

For individuals who learn a number of my 10 takeaways and tactical deep dives, it received’t be breaking information that the Celtics have been at their finest with Kornet on the court docket. As we see on the chart beneath, the Celtics’ backup massive man was on the ground when Joe Mazzulla’s crew was successful the margins—and the scoring differential.

Additionally, some gamers have been nonetheless extremely constructive regardless of not performing notably properly within the possession battle—reminiscent of Derrick White or Jayson Tatum. There have been additionally gamers who helped the crew dominate the possession battle however weren’t as impactful on web ranking, 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 have been extra more likely to win the possession battle and have a greater web ranking when these three have been on the bench.

Total, this reveals that the Celtics have been capable of play two types of basketball: the five-out spacing with the starters, and the gritty possession battle with the bench. And while you combine all of it, you find yourself with an important common season. This additionally demonstrates that successful the possession battle is vital—however not all the time sufficient to win. Additionally, be aware {that a} participant’s influence on the possession battle relies upon closely on context and function optimization. In the present day, Kornet is among the finest gamers at serving to his crew win that battle. Earlier in his profession, in a special context with completely different assignments, he was one of many least impactful gamers on that finish.

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