The Celtics that finish the 2025-26 season will almost certainly be different from the team we’re looking at right now. Whether it’s trades, cuts, or signings, Brad Stevens is certainly making up for all the downtime over the past couple of seasons.
In a way, he’s creating a similar rite of passage for Joe Mazzulla that he experienced as a head coach. ‘
Stevens came to Boston in 2013 in the wake of the Paul Pierce/Kevin Garnett trade that gutted the Celtics. That move was much more extreme than the Jrue Holiday or Kristaps Porzingis deal, and it ushered in a much more definitive rebuild than what the Celtics are facing now, but it still was a team in flux.
Stevens overachieved with his group, starting in his second season when Isaiah Thomas helped fuel an improbable run to the playoffs. Stevens never missed a postseason after that.
While this summer’s moves have left Mazzulla with great players in Jaylen Brown and Derrick White, good role players in Payton Pritchard and Sam Hauser, and eventually, the return of Jayson Tatum, the roster around the healthy remaining Celtics is a hodgepodge of young players and castoffs.
In a best-case scenario, a few of those guys hit, Tatum returns at the end of this season or the beginning of next, and Boston vaults back into being a contender. Worst-case, though, is that none of them amount to much, and next year’s team is stuck trying to figure out supporting pieces again.
This is where Mazzulla becomes incredibly important.
“I'm excited to see what this team has in store,” Stevens said. “I know Joe's excited. Joe's teams, they're trying a bunch of stuff out there now with our Summer League team that we haven't done in the past that I think will be good experimentation at the very least. But that's kind of what we want to make sure we're ready to maximize this group."
This is a new challenge for Mazzulla. He lucked into a ready-made winner after the Ime Udoka situation and quickly figured out what buttons to press to get the team over the top. He couldn't get his team to repeat that feat and now four key players are gone. If they're going to get back to the top of the NBA, Mazzulla is going to have to get his guys to over-perform not just this year, but many years moving forward.
“I think the scariest thing is, like, if you plan on coaching or playing for a long time, if you look at the ratio outside of like John Wooden, Red Auerbach, and Phil Jackson, the ratio of like successes to failures weighs heavier on the failure side, if you count not winning a championship as a failure,” Mazzulla said on Julian Edelman’s podcast this week. “And so that space of (being) happily miserable is somewhere where you got to be extremely comfortable, because I think that's where you grow the most.”
Mazzulla’s growth is going to be on display this upcoming season. Some of that will come in the form of patience and knowing when to let guys play through mistakes and when to sit them down. Some of it will come in lineup decisions and figuring out which players are maximized in certain combinations. And some of it will come with creative play calling on both offense and defense. We’ll get a taste of that in a few days.
“We're going to do some different stuff,” said Celtics assistant coach Matt Reynolds, who is serving as the summer league team’s head coach in Las Vegas. “We had a decent amount of time to prepare over the course of last handful of weeks, get some idea of who's gonna be on the team and come up with some ideas of how we want to play. And then these last few days have been a building process.”
It’s going to be tough sometimes to see exactly what the Celtics are working on in Vegas. The team has only just begun working out together and the roster is full of guys trying out for scouts in attendance, so certain plays will be broken by guys looking to show they can do certain things.
However, we can get some sense of what the Celtics are trying to accomplish just by how things start. Maybe they throw some more zone defense out there or they work on certain offensive configurations that, even if they go awry, give us some sense of a direction.
The good news is the Celtics are on record as saying they need to try some new things this year. Mazzulla has always known he’d have to change as a coach no matter what the situation. Now he’s being given something much different from what he’s had, and he’ll have to adapt.
“You always have to evolve,” Mazzulla said on Edelman’s podcast. “As long as you can become authentic to who you are as a leader, people will respect that, and they'll go with it. And it doesn't mean it's gonna be perfect all the time. I just think it's constantly evolving because people are different and personalities are different.
“To be a great coach, you have to have great players. You have to have a group of players that allow you to be yourself. And I think you have to create a space where you allow your players to be themselves. So I think that identity, where I think it is being authentic to who I am -- I'm not afraid to say, like, here's where I suck, here's where I'm pretty good. Here's where I need you guys to fill in for me. Here's how we can do it together.”
A lot of people will have to come through in a big way for the Celtics to get some kind of payoff from the risks they're taking this summer. Mazzulla might be at the front of the line. Friday will give us the first glimpse of what he might have up his sleeve.