Celtics Insider Explains Why Joe Mazzulla is Facing Biggest Test Yet This Year

Boston Celtics team president Brad Stevens may have constructed his 2025-26 roster with a clear mandate to save money, but that doesn't mean head coach Joe Mazzulla and the players on the floor won't try to win as many games as they can.

Christopher L. Gasper of The Boston Globe writes that this upcoming season will represent a major opportunity for Mazzulla to strut his stuff as a coach.

During his first season, when he stepped in for the fired Ime Udoka, Mazzulla led Boston to a 57-25 record and the Eastern Conference Finals, in which they pushed the Miami Heat to seven games.

Cumulatively, Mazzulla has led the Celtics to a 182-64 regular season record and a 33-17 playoff record, including an NBA Finals victory in 2024. For his efforts, the team inked him to a long-term contract extension this offseason, even as it faces a major personnel transition.

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Six-time All-Star power forward Jayson Tatum tore his Achilles tendon during the Celtics' eventual second-round defeat to the New York Knicks this past spring, and is likely to miss the entire season. Without Boston's best player available, Stevens decided to get below at least the NBA's punitive second luxury tax apron — although he remains pretty close to the first as of this writing, and may look to shelve further salaries.

"Mazzulla is a good coach. It was a fait accompli that the Celtics were going to award him a contract extension. He wields the unwavering support of both Tatum and Celtics president of basketball operations Brad Stevens," writes Gasper.

This Year Will Be Mazzulla's Biggest Test Yet

"But we’ll learn just how good a coach Mazzulla is when, for the first time as Boston bench boss, he’s not dealing with a ready-out-of-the-box championship contender," Gasper allows. "It’s time for him to turn Erik Spoelstra and get his team to punch above its weight."

Gone are starters Jrue Holiday and Kristaps Porzingis, plus key reserve Luke Kornet and (probably) beloved sixth man power forward/center Al Horford. In their stead, Boston has acquired guard Anfernee Simons and rookie two-way wing RJ Luis Jr., while also signing free agents Chris Boucher, Luka Garza and Josh Minott.

The Celtics also selected three rookies, but only former Real Madrid swingman Hugo Gonzalez will be on the team's regular season roster to start the season.

"But even if Mazzulla wasn’t handed a less talented team there needed to be a philosophical shift from Total Mazzulla Math after witnessing the Celtics shoot themselves in the sneakers in the Eastern Conference semifinals against the Knicks," adds Gasper.

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Gasper notes that Boston gave up a pair of 20-point second-half edges in the first two home games of that Knicks series thanks in large part to an overreliance on 3-point shooting, and a reticence to take the ball inside.

"The best coaches mold their system to their talent, not the other way around. They maximize strengths and minimize weaknesses," Gasper observes. "Mazzulla must be first willing and then able to adapt to the team he has now, not the ones he coached in the past to great success. Mazzulla sports a 182-64 regular-season mark (.740 winning percentage) and is 33-17 (.660) in the playoffs as Celtics coach."

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