Last season, the Celtics were just the third team in the 27 years for which we have play-by-play data to finish in the top three in both offensive and defensive efficiency in the regular season. And then they became the first of those three teams to not win the championship.
The Celtics have the league’s longest active playoff streak (nine years) and statistically, they’ve been the league’s best team (plus-5.5 points per 100 possessions) over the last four seasons. But their last championship came in 2008, and their loss in the Eastern Conference Finals this year was a disappointing finish given how good they were in the regular season.
General manager Brad Stevens could certainly have chosen to run it back, with Jayson Tatum and Jaylen Brown still just 25 and 26 years old, respectively. Joe Mazzulla now has a year of experience as a head coach and a stronger staff around him.
But Stevens chose to shake things up, essentially trading Marcus Smart for Kristaps Porzingis, while also parting ways with Grant Williams. So the Celtics are hoping that a new formula will get them over the hump.
— Boston Celtics (@celtics) June 23, 2023
Here are some notes and film on how Porzingis gives them a new look.
1. Off the catch
According to Synergy tracking, 27.2% of the Celtics’ possessions, the league’s highest rate, were “spot-up” possessions. And they ranked third in spot-up efficiency (1.12 points per possession).
The definition of a spot-up possession is “when the possession-ending event is a catch-and-shoot or catch-and-drive play.” The Celtics ranked just 17th in ball movement (314 passes per 24 minutes of possession), but they were fifth in assist rate, recording assists on 63.2% of their field goals. They shot and attacked off the catch.
Spot-up possessions are also how Porzingis scored a plurality (22%) of his points, according to Synergy. He’s a big target, who generally spaces a few feet beyond the 3-point line. Even if he doesn’t have a ton of space, he can shoot over big defenders …
Porzingis has made 737 career 3-pointers, more than twice as many as any other player 7-foot-1 or taller. He’s shot much better on catch-and-shoot 3s (36.7%) than Smart (34.2%) over the last three seasons. And despite his size, he’s also solid when he puts the ball on the floor, able to finish with some finesse and touch …
The 1.08 points per possession Porzingis scored on spot-ups ranked 57th among 126 players with at least 200 spot-up possessions.
2. Shoot first
With the departure of Smart, the Celtics have lost some playmaking. And they’re not getting much back with the addition of Porzingis. His overall assist rate (11.6 per 100 possessions) ranked 48th among 54 players with a usage rate of 25% or higher and he recorded assists on just 3.3% of his drives, the fifth lowest rate among 190 players with at least 200 drives last season.
He’s a scorer, who’s more likely to shoot from 8-18 feet (not an efficient place to be shooting from) than make the next pass …
The Celtics still have Malcolm Brogdon and Derrick White, but Smart’s departure clearly puts more playmaking burden on the shoulders of Tatum and Brown.
3. Post presence
The Celtics ranked 26th with just 3.8 post-ups per game last season, and Smart was second on the team with 1.1. Porzingis averaged more than his new team, ranking 12th in the league with 4.0 post-ups per game, according to Second Spectrum tracking.
That’s not a lot, but Porzingis’ 86-for-141 (61.0%) shooting on post-ups was the second best mark (trailing only that of Nikola Jokic) among 17 players with at least 100 field goal attempts out of the post. And he had a higher free throw rate (46 attempts per 100 shots from the field) out of the post than Jokic.
Porzingis was mostly defended by opposing bigs last season, but the Indiana Pacers actually had Buddy Hield on him to a large degree. That didn’t work too well, and Porzingis can take advantage of a mismatch …
… though he’s not exactly burying wings under the basket …
4. Playing small
Really, for a guy who’s 7-foot-3, Porzingis doesn’t play inside all that much. Last season, 46% of his shots came in the paint, a rate that ranked 146th (right in the middle) among 292 players with 250 total field goal attempts. He can take advantage of a mismatch, but he doesn’t consistently look to do so …
For some bigs, the immediate reaction to getting 6-foot-4 R.J. Hampton switched onto you is a move into the post. Porzingis isn’t always going to have that mentality.
5. The other end of the floor
The Celtics have had a top-five defense in three of the last four seasons because they’ve had several good or great defenders. Smart, of course, was the Defensive Player of the Year in 2021-22. He’s strong, tenacious and … well, smart.
Porzingis is obviously a much different defender, a natural rim protector at 7-foot-3. He’s the only player in the 44 seasons of the 3-point line to average at least two 3-pointers and at least 1.5 blocks in multiple seasons, doing it in 2019-20 and again last season. And he’s had some strong rim protection numbers over the years, though last season’s numbers – opponents shot 56.1% at the rim when he was there – weren’t close to his best.
He can have a real presence on that end of the floor …
With his mobility, he can defend a ball-handler and recover to stop the roll man. He’s not out of control, so he can stay on balance and rebound his own blocks.
But he’s not going to be the best defender against the Eastern Conference opponent the Celtics likely fear the most …
Porzingis will likely be paired with Al Horford or Robert Williams III in Boston, with the latter pairing being similar to the Porzingis-Daniel Gafford tandem in Washington last season. The Wizards were very good in 490 total minutes with Gafford and Porzingis on the floor together, outscoring their opponents by 5.8 points per 100 possessions.
But that success was more about offense (121.4 points scored per 100) than defense. And with Porzingis now replacing Smart in Boston, the Celtics are more likely to remain in the top five on the offensive end of the floor.
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John Schuhmann is a senior stats analyst for NBA.com. You can e-mail him here, find his archive here and follow him on Twitter.
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