LAS VEGAS — Joe Mazzulla sits back in his chair at the corner of practice as music blasts. It’s Celtics Summer League, and a new crop of players are beginning their journey to the pros.
Some, like first-round draft picks Hugo Gonzalez and Chris Cenac Jr, come in with plenty of expectations and fanfare. Others are hoping to break through, to make some sort of name for themselves, to get their dream opportunity.
As the 16-player Summer League squad wraps up practice, Neemias Queta is partaking in a rigorous
workout with the Celtics assistant coaches. The Portuguese center is just a few days removed from signing a life-changing contract, a 4-year, $56 million extension that is the result of years of tireless work.
Fittingly, as he walks into the gymnasium, he shakes nearly every reporter’s hand. We each shower him with congratulations. After all, it’s not every day that a player who jumped around from two-way contract to two-way contract gets that kind of long-term payout. Just two years ago, Queta was a Summer League player himself, hoping to one day become an impactful rotation player.
Outside of Queta’s entrance, it feels like a normal day of practice: Mazzulla is in the background, chatting with some staff members. Queta is working on his post moves with assistant coach Tony Dobbins. A smattering of assistants work with players on their skill development.
But the reality is that it’s been anything but a normal couple of weeks for the NBA’s most storied franchise.
Just over a week ago, the front office made the difficult and highly-scrutinized decision to trade Jaylen Brown, the team’s longest-tenured player, the Finals MVP who over the years became a staple in the Boston community. It’s a decision that Brad Stevens fielded dozens of questions about in a 40-minute press conference earlier in the week.
“This is the decision we came to,” Stevens said, “and obviously, in many circles that’s not popular, and we understood that coming into it.”
But lost in the shuffle of the Brown trade was everything else that took place over the last few weeks — the Celtics signed veteran free agents Mitchell Robinson and Mike Conley, acquired Paul George, and extended Neemias Queta and Ron Harper Jr long-term, two hardworking players who began their tenures with the organization in the G-League.
They also drafted two rookies — Chris Cenac Jr. and Dillon Mitchell — whose addition to the franchise got buried amid all the trade hysteria.
I sat down with Mazzulla to talk through it all: through the defining move that sent Jaylen Brown to the rival Philadelphia 76ers, through the offseason additions he hopes help the team ultimately achieve its loftiest goals, and through his own journey as, believe it or not, one of the NBA’s longer-tenured coaches.
This is the first in a two-part series diving into the Celtics coach’s mindset on the heels of a disappointing playoff exit, his thoughts on the team’s newest additions, and much more.
Joe Mazzulla and the Celtics coaching staff looked inwards
The reality is that the Jaylen Brown trade came on the heels of a season that ended in undeniable disappointment. The Celtics held a commanding 3-1 series lead over the Philadelphia 76ers, but lost three straight games, becoming the first group in franchise history to blow a 3-1 lead.
As such, he and his coaching staff have been handily criticized all summer.
When I ask about that flood of criticism — a sharp departure from the flowers they received during an unexpected 56-win campaign — Mazzulla interrupts me.
“As we should be,” Mazzulla said. “That’s deserved criticism. One, you don’t end your season on a loss. Two, you’re up three games to one. You have to be able to win a game, and we don’t. So that starts with me.”
The Celtics notably have the exact same coaching staff back for a third consecutive year. That staff, headlined by coaches like Sam Cassell, Dobbins, DJ MacLeay, Matt Reynolds, and others, has been working tirelessly this summer to figure out where things went wrong in the playoffs, and how they can grow from there. It’s a process that began almost immediately after the playoff exit.
“It starts with me,” Mazzulla said. “Where can I get better? Where did I fail in the last two postseasons? Where do I have to be better? And then it trickles down to asking them the same questions.”
“You have to be honest with yourself. You have to have people who are honest around you, and I don’t think I’ve ever been around a group of guys who are more honest with each other. And we argue constantly. The most important thing is getting to the right answer.“
Aside from the self-reflection, the Celtics coaching staff had a busy summer of their own, with several emerging as finalists for NBA head-coaching jobs. Dobbins was a finalist for the Dallas Mavericks head coach job, and fellow assistant coach Tony Lashbrook was a finalist for the Portland Trail Blazers job, among others.
Mazzulla welcomed it all.
“We had four coaches have head coaching interviews this summer, and two other guys have interviews at other jobs,” Mazzulla said. “And so I think those are little affirmations that the process of what we’re doing is good.”
Joe Mazzulla emphasizes Jaylen Brown’s competitiveness
Mazzulla smiled when I asked him about Brown, whom he worked with for four seasons as head coach. Together, they won almost 300 games and ultimately hoisted the coveted Larry O’Brien trophy.
More than anything, Mazzulla credits the five-time All-Star for making him better. Speaking to a group of reporters just a few minutes earlier for the first time since the trade, Mazzulla shared how difficult the trade was and stressed that Brown made him a better coach: “I know that for a fact.”
“Something like that is going to be difficult,“ Mazzulla said. “But I think if you could just get through it and act as if nothing happened, then that’s when I think that you’re not in it for the right reasons.”
As we later sat on the gymnasium sidelines, I asked Mazzulla to elaborate on the notion that Brown made him better.
“The biggest thing was just his competitiveness,” Mazzulla said. “He wasn’t afraid to push you. That was for teammates. That was for me. That was for people. He wasn’t afraid to hold you accountable to a higher standard. And when you have the opportunity to coach guys like that, it just makes you better.”
What does Mazzulla hope Celtics fans don’t miss when they reflect on Brown’s tenure in Boston?
There’s the well-chronicled off-court work that will forever define his tenure. There’s the 2024 championship, in which Brown raised nearly every aspect of his game to its best version.
There’s the 2025-2026 season, in which he built a legitimate MVP case for the first time in his career.
“I really hope people saw the competitiveness,” Mazzulla said. “I hope people saw the leadership. The leadership jump that he took this year… I hope people [were able to] see that.”
“What you see is what you get from Jaylen: it’s competitiveness, it’s respect. And he wants to win.”
Making the most of the Celtics’ offseason additions
With Jaylen Brown in Philadelphia, the Celtics coaching staff has been tasked with figuring out how to get the most out of players like Mitchell Robinson and Paul George.
Brown isn’t going to be replaced — that’s not the goal — but Mazzulla’s job is to figure out how to get the most o
“You’re getting rid of strengths [in Jaylen], but you’re bringing in new strengths,” he said. “And that’s the part that we have to leverage as a staff and as a team.”
“Bringing in the strength of Paul George, bringing in the strength of Mike Conley, guys that have beaten us in games, and guys that have played high-level basketball for a long time. Bringing in the strength of Mitchell Robinson, who has been one of the most impactful players when he’s on the floor. And so we just have to have an understanding of what those guys’ strengths are, and how do we give them an opportunity to make us better?”
Robinson is the Celtics’ marquee free agency signing; the longtime New York Knicks center is a historic rebounder who has long been a thorn on the Celtics’ side.
When the Knicks and Celtics faced off in the 2025 playoffs, Joe Mazzulla ordered his players to routinely send Robinson — a notoriously poor free-throw shooter — to the foul line to try and get him off the court. Regardless of that strategy, the Knicks outscored the Celtics by 46 points in Robinson’s minutes that series.
So, when it came time to offer Robinson a contract last week, it was a full-circle moment. In that free agency call, the two discussed Mazzulla’s Hack-a-Mitch approach.
“I told him [the fouling] was a compliment,” Mazzulla said. “He was so effective when he’s on the floor. We had to do what we could to take him off the floor. So, now we have to be able to use his effectiveness to make us better. And I think it gives us a ton of depth at the center spot where two guys have done so many great things for us, Neemi and Luka [Garza]. And now we have another guy that can help us.”
Neemias Queta, Ron Harper Jr see their work get rewarded
For Celtics fans, some of the best news of the offseason came when Queta signed his extension, and Ron Harper Jr. signed his own $4-year, $14 million contract.
It’s something that was gratifying to Mazzulla, too.
“They put their head down, and they work,” he said. “And I think it’s a testament to the front office for finding guys that can impact winning, and then it’s a testament to the player development staff, and then it’s a testament to the players with how hard they work.”
There were distinct moments in which it became clear to the Celtics head coach that Queta and Harper Jr. had what it took to make it in this league. For Harper Jr., it was the way he was able to crash the glass and defend in a February road game against the Houston Rockets in which he was tasked with guarding Kevin Durant.
For Queta, it was the way he embraced the illustrious responsibility of being the Celtics’ starting center from the get-go.
“They both just showed moments,” Mazzulla said.
Now, both players will be Celtics long-term.
On top of those additions, the Celtics added two rookies via the draft: Chris Cenac Jr and Dillon Mitchell. They weren’t projecting Cenac would be available at pick No. 27, but he had slipped through the first round.
“Obviously, didn’t expect to get him at this point, and I think that’s the conversation that you have with Chris of like, ‘Hey, you’re here for a reason,’” he said. “One, you need to find out why you got to us, and you need to use that as leverage, and you need to use that as information to become the best player that you possibly can.”
Mazzulla pointed out that Cenac and Mitchell come to him after being coached by “high-level” coaches: Cenac was led by Kalvin Sampson at Houston and Mitchell by John Calipari at St. John’s. He expects that will make their adjustment to the NBA’s intensity a little easier.
“I think that really helps guys at the next level, when you’ve been coached by great coaches,” Mazzulla said. “I think it makes it easier for them.”
Looking ahead at Year 5 in Boston
As Mazzulla prepares for his fifth season as head coach of the Celtics, he feels more gratitude for the job than ever before.
“The gratitude [grows] the longer you get to stay, because you know there’s so much turnover,” he said.
He’s not wrong: remarkably, only six NBA coaches have been with their franchise for longer than Mazzulla has.
As such, he’s been studying veteran coaches like Erik Spoelstra, Gregg Popovich, Steve Kerr — decorated coaches who spent their entire coaching careers with one organization — as well as New York Knicks head coach Mike Brown, who has moved around a few times, but found success wherever he’s gone.
What’s allowed them to be effective for so long?
“It’s not supposed to go one way,” Mazzulla said. “You just have to get better, and you have to be around great people. And I’m fortunate enough to do that here.”
The second part of my exclusive conversation with Joe Mazzulla will be out on Monday — a deeper dive into the unique way the Celtics head coach has spent his offseason.
