Joe Mazzulla’s smirk suggested the memory, once painful, had become a reason for great optimism. For as completely as Kristaps Porziņģis overwhelmed the Boston Celtics in his last meeting against them, he would be playing for them in the near future. One chair to Mazzulla’s left, Porziņģis smiled. The newest member of the Celtics was sitting at his introductory press conference in June 2023. A few months earlier, he had been the team’s biggest problem for a day.
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No matter what defensive coverage Mazzulla dialed up, the center beat it. He punished the Celtics when they switched, consistently scoring over the top of Marcus Smart, Jaylen Brown and Jayson Tatum. Even when Boston didn’t switch, Porziņģis took advantage of the team’s big men. He swished an and-1 over Grant Williams’ head. He blew by Robert Williams III in transition. He ended the first half with a one-dribble pull-up against Al Horford.
As Porziņģis scored 32 points that day for Washington, the post-ups hurt Boston more than anything else. He made quick work of smaller defenders. He fought to get to his spots. He wasted no motion in his moves. The Celtics, throughout one of their worst losses all season, could not steer him away from his desired shots. Boston’s top defenders, some of the best in the league, were nothing more than traffic cones for Porziņģis to operate around.
Six months after Mazzulla’s smirk, Porziņģis is delivering one of the most efficient post-up seasons since the NBA began sharing play-type data publicly. He is one of the biggest reasons to believe the 62-17 Celtics, after two disappointing exits deep in the playoffs, are now better prepared to score against the best defenses. Boston already had one of the league’s highest-scoring duos in Tatum and Brown, but Porziņģis’ inside-out punch has filled the holes around them. Mazzulla says the big man’s interior presence has altered the way defenses match up with and strategize against the Celtics, who will enter the upcoming playoffs as the top seed in the Eastern Conference.
“Those were some of the shots that we didn’t take in late-game situations in the past or even close games or even throughout the game in general,” Mazzulla says. “So just his efficiency to be able to score at those levels gives us a different dynamic offensively.”
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If Porziņģis is the Celtics’ fix, as they hope, it will be because of all the numbers he digested to fix himself.
Years ago, during his time with the Dallas Mavericks, the organization saw his post-up opportunities as wasted possessions. Then-Mavericks head coach Rick Carlisle once went on a memorable rant explaining why, mathematically, throwing the ball to Porziņģis down low didn’t make sense. At the time, the advanced analytics showed that the Mavericks, who led the league in offensive efficiency, were basically punting away points any time they fed him in the post.
The numbers, which steered Dallas away from that part of Porziņģis’ game, were not wrong. So how did he transform them so drastically? How did he learn how to maximize his towering 7-foot-2 height and soft touch near the basket? How did he become one of the league’s most efficient players there – and, as Mazzulla understood, a nightmare for opposing coaches?
By submitting himself to the same advanced analytics that revealed his shortcomings. At a stage of his career where he could have simply accepted his place in the game, Porziņģis instead shifted the numbers in his favor by learning everything about them. He allowed the numbers to dictate his practice habits and his moves. Working with a close friend, he armed himself with the deepest knowledge of his strengths and weaknesses and recalibrated his game until the numbers showcased his progress.
“The numbers don’t lie,” Porziņģis says.
The numbers didn’t just tell Porziņģis the truth. Once he opened his eyes to them, they laid out the path for him to follow.
The eight-inch height difference in the matchup suggested Porziņģis, the tallest man on the court, should score with ease. But even in basketball, size doesn’t mean everything. When the Los Angeles Lakers assigned Danny Green to defend Porziņģis in a 2019 matchup, the man in charge of the Dallas Mavericks’ advanced analytics, Bob Voulgaris, recognized his team staring at a likely checkmate.
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“We’re f—–,” Voulgaris messaged one of the team’s assistants. “We’re done.”
During the Mavericks’ previous meeting with the Lakers, Anthony Davis spent most of his time following Porziņģis around the perimeter, leaving the paint open for Luka Dončić to control. The Mavericks rolled like an avalanche during the third quarter of that game. Dončić repeatedly found solutions against pick-and-roll coverage while the need to shadow Porziņģis took away the rest of Davis’ defensive impact. Not even one of the league’s best shot blockers could smother opponents at the rim while chasing a center at the 3-point arc.
As Voulgaris spotted quickly, the matchup switch eliminated that advantage. A less informed bystander would have just called for Dallas to feed Porziņģis consistently on the low block. During his first healthy season with Dallas, the big man’s unique combination of size and skills had helped transform the team into the league’s most potent offense. Still, at age 24 and working his way back to top form after a torn ACL forced him to miss the 2018-19 season, he had not yet developed ways to damage opponents down low. He scored an unsightly 0.81 points per post-up possession that season. For the Mavericks, who set what was then an NBA record of 1.16 points per possession, the math didn’t come close to justifying consistent Porziņģis touches down low.
The Mavs did run a Porziņģis post-up once early in the first quarter. With Avery Bradley on him, Porziņģis turned over his right shoulder and bricked a fadeaway jump shot. With Davis no longer stapled to Porziņģis’ side on the perimeter, the Mavericks, on their way to setting that NBA record for offensive rating in a single season, had no more answers left. They fell shy of the 100-point mark for the second time all season, notching a season-low 95 points.
“It’s like specifically,” Voulgaris said, “your post-ups aren’t that efficient.”
Žanis Peiners did not instantly recommend himself when Porziņģis called for suggestions on a new coach to work with during the 2022 offseason.
Peiners and Porziņģis competed with each other on the Latvian national team. They are good friends despite being different types of people — maybe even because they are different. As Peiners puts it, Porziņģis can be driven by his emotions. Peiners uses a more analytical approach toward life. Their contrasts helped bring them together.
“It was always fun,” Peiners says. “And always a fight.”
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At Porziņģis’ request, Peiners thought of several coaches who could take Porziņģis to the next level. One coached a women’s team and probably wouldn’t have much time to work with him. Another seemed like he would be too old school to embrace new-age tactics. The mental approach of a third coach would clash with Porziņģis’ personality. Only after failing to come up with the right coach did Peiners think to recommend himself. He watched all of Porziņģis’ games anyway. Not long after the end of a nine-year professional career overseas, Peiners had free time. He could do it.
“That’s what I honestly wanted to hear,” Porziņģis told him, “but I didn’t want to ask.”
After the Mavericks traded him to the Wizards during the previous season, Porziņģis recognized himself at a crossroads in his career. After his time with the Mavericks made it clear he wasn’t good enough posting up to command more opportunities, he believed he would need to either learn how to thrive in such scenarios or essentially eliminate the craft from his game. Settling on the former option didn’t take much thought for him. He didn’t want to give up on the goal of becoming an all-around scorer. That meant he would embark on a journey to revamp his game.
Peiners and Porziņģis initially agreed to work together for two weeks. If the partnership worked, they would keep it going. During the first conversation about their direction, Peiners informed Porziņģis he would not simply put him through drills. Any coach could do that. Peiners would use analytics to shape his lessons. He would dive deep into the numbers to determine what Porziņģis should use most and what parts of his game should be eliminated. If Porziņģis had any questions about the methods, Peiners would point him to the answers in the data. Seven years into Porziņģis’ career, including one season wiped out by a torn ACL, the results have produced a large enough sample size to reflect the reality of his game.
“Those numbers were already pretty much objective,” Peiners says. “And he could not argue with me because I always had numbers.”
Peiners had all the numbers. All the conceivable ones, at least. He examined efficiency in all sorts of scenarios. He learned how Porziņģis’ accuracy changed depending on how many dribbles he took. He explored how he fared from different spots on the floor. He found out how well Porziņģis did on banked shots and how well he shot the ball straight through the hoop. He looked at the data on when he turned to his left and when he turned to his right. Peiners broke down every detail he could. Though his work was exhaustive, he sought additional opinions because he didn’t want to miss anything. Among other outside sources he leaned on, he urged Porziņģis to pick the brain of one of his new assistant coaches in Washington, Dean Oliver, a legend in the field of basketball analytics. Pieners wanted to hear Oliver’s view and vision.
Peiners did not limit his studies simply to Porziņģis’ game. Peiners researched other tall and lean players who excelled in the post, including Dirk Nowitzki and Kevin Durant. Peiners also analyzed which skills were more possible for players to develop later in their careers. He aimed to trim the fat off Porziņģis’ low-post arsenal.
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“You have some things (where you are) very, very efficient and very good,” Peiners explained, “and some things probably you will never do amazingly. So let’s try to be very good at something, be very efficient at something, and let’s try to take away non-efficient things.”
While others accepted his limitations as lasting, Porziņģis banked on the idea he could break out of them. Though much of the league was pivoting away from post-ups, he had unusual advantages as a 7-foot-2 sharpshooter. After failing to buy in fully to the analytics during his time in Dallas – “because I didn’t understand it,” he says – chats with Peiners helped him see their importance.
“At first, I was still like, ‘Get out of here,’” Porziņģis says. ‘He said, ‘I don’t know. You’re not efficient, you need to do this, you need to do that.’ So once we got comfortable having those conversations, that’s when he really helped me.”
Their days together were long. Before workouts, Porziņģis liked to drink one coffee, then another. Afterward, he and Peiners would sometimes grab another coffee and a bite to eat. By the time they wrapped up everything, they had often spent six or seven hours together. Peiners tried to pack as much teaching as he could into that time. He only shared details supported by the analytical evidence.
“I’m taking those hours to give him that information and try to explain it,” Peiners says.
Porziņģis might not have been open to such a style earlier in his career, but his experience in Dallas left him with an urgency to explore new avenues. During his final playoff series with the Mavericks, the coaching staff asked him to consistently stay in the corner to space the floor, believing he would be more useful than if he were directly involved in the action. When the organization traded him to Washington months later for Spencer Dinwiddie, Davis Bertans and a future second-round pick, the price showed how much Porziņģis’ value had diminished. Rocky health factored into his up-and-down stint in Dallas, but he still calls his time with the Mavericks a reality check.
“I didn’t understand (the analytics),” Porziņģis says, “or didn’t have the guide, or somebody to guide me. Like, ‘Hey, let’s try to do this.’ So that’s all that was. But once I took that responsibility, and worked on it, and fixed it, it’s been up from there.”
The end in Dallas motivated him. Humble enough to recognize the truth in the numbers, Porziņģis bent them in his direction.
In Washington for 1 1/2 seasons, Porziņģis consistently sought Oliver’s counsel. During film sessions, he requested more information.
“What KP likes is he likes kind of the straight answer,” Oliver says. “Like OK, not just, ‘This is a good shot’ or, ‘This is a bad shot.’ ‘OK, what does that mean? What’s the chance that shot will go in?’”
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The extent to which Porziņģis cared about the advanced analytics surprised Oliver, who had heard from a former Mavericks coach not to expect the 2018 All-Star to be receptive to such talk. Porziņģis approached Oliver more than the other way around. When they talked, Oliver could see the details registering in Porziņģis’ brain. On the court, he noticed him responding to the discussions. After sessions, Oliver says, Porziņģis changed his behavior to reflect the lessons.
He eats it up, Oliver recalled thinking.
The more Porziņģis learned about his game, the more efficiently he operated. He kept an open mind about ways he could grow. The Mavericks also did studies on his game, according to Voulgaris. He says they found that when Porziņģis dribbled more than twice, whether he was driving or stationary, “It was quite bad news.”
Peiners accepted that Porziņģis would never become a great dribbler and would need to find other ways to thrive. On the block, Porziņģis’ bank shots were typically more efficient than when he directed the ball straight through the hoop; he started using the glass more frequently.
The Wizards found that his accuracy dipped when he faded away from the hoop; he committed to either going straight up or toward the basket. Washington’s coaching staff shifted him around the court with more flexibility than he ever enjoyed in Dallas. The system helped him feel comfortable. Among other go-to spots, he favored operating at the free-throw line.
“The shot from the foul line historically, analytically, is not a great shot,” Oliver says.
It still worked for Porziņģis. From there, he often drained shots or drew fouls.
Though it might sound counterintuitive for a player hoping to excel in the most physical areas of the court, Porziņģis stopped trying to bulk up the way he did in Dallas. With the Mavericks, he believes a desire to add muscle hindered him. He felt increasingly comfortable as time distanced him from the 2018 injury.
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“I would say I was probably even stronger in Dallas than I am now, physically, because that’s all I was doing,” Porziņģis says. “Lifting weights and trying to be as physical as possible. But honestly, my handles were off. My shot was not perfect. It hurt me more than it helped my game. For a few physical situations, maybe it helped me. But in general, especially early on, I was rusty coming back from the injury (a 2018 torn ACL). And then, I’d get in the post, and I’d dribble off my foot every other time. I was like, ‘Man, what the hell’s going on here?’ So definitely lost some rhythm and some confidence in that, but regained it. And regained it through looking at myself realistically, looking at myself in the mirror, and fixing those things.”
Peiners helped Porziņģis strip away about 50 percent of his game and focus on what he objectively did best. Their workouts concentrated on steering him toward the spots and moves that worked for him.
“First of all I would try to say that this is not so much of my part in this, but how good he is taking this information and soaking it kind of,” Peiners says. “It’s insane because some things you can tell him or teach him and next game or next week he’s already doing them on the court or in a game. He is amazingly talented in that part. He’s really listening, he’s really trusting those numbers, and it’s amazing.”
Even Peiners did not expect the work to pay off the way it did. In Washington, far from the NBA spotlight, Porziņģis developed into one of the league’s most efficient post-up players. During his only full season with the Wizards, he averaged 1.18 points per post-up possession on high volume.
Peiners calls the change in efficiency “crazy.” He believes Porziņģis, entering the normal prime years for a professional basketball player, would have come into his own even if he had ignored the advanced analytics forever. The center’s willingness to seek additional help only bolstered his rapid development. The lessons worked quickly.
“And they are still working,” Peiners says. “He’s getting better those two and a half years, he’s improving, by his decisions. Every game, every month, you can see an improvement. So yeah, I still think he has room to grow.”
Nobody on Porziņģis’ side panics anymore when the other team slides a smaller player onto him.
If anything, the Celtics have needed to work on finding him more frequently in such situations. Sometimes, even with Tatum and Brown on the floor, their best option is to throw an entry pass to Porziņģis and let him cook. The talent around him has only enhanced his efficiency in the post. With all the floor spacers on the Celtics’ roster, opponents need to limit their help and double teams. In that environment, Porziņģis has feasted on switches.
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Indirectly, his evolution landed him in Boston. The Celtics valued the parts of his game he remodeled most. They needed his post-up talent and they have utilized it well. Since joining the Celtics, he is averaging 1.30 points per post-up possession, which would rank third among players with at least one post-up attempt per game in a single season dating at least to 2015-16. It remains to be seen whether Porziņģis will help Boston solve long-standing postseason issues, but acquiring him helped to diversify what has been the NBA’s most potent offense.
As well as Porziņģis has fit in Boston so far, the playoffs will hit him with new challenges. Peiners expects opponents to ratchet up their physicality. He believes drawing fouls should become more difficult with the additional contact allowed.
“Efficiency will drop,” Peiners says, “and then you need to adjust.”
Though he doesn’t have much playoff experience, Porziņģis has proven to process adjustments quickly. These days, he looks back on his time in Dallas as a catalyst.
“Looking back, I appreciate much more what Bob was doing with us, and Rick Carlisle too,” Porziņģis says. “I just wish I was a bit more ahead of those numbers and the things that we were trying to do. That would’ve helped me.”
It also would have benefited the Mavericks.
“Where we really failed I think in some ways was not having the coaching staff, not working on making him a more efficient post-up player,” Voulgaris says. “Maybe there’s this idea that, and I think I may be guilty of this, like, ‘This is what a player is because this is what the numbers say.’ But it’s not necessarily what he can be going forward.”
Porziņģis is now proof of how much a player can change. In the post, he has transformed from a liability into a dominator. His shaky numbers back then were not wrong. They just weren’t forever.
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(Illustration: John Bradford / The Athletic; photos: Paul Rutherford, Ronald Martinez / Getty Images)
