{"id":746379,"date":"2026-05-28T17:57:16","date_gmt":"2026-05-28T17:57:16","guid":{"rendered":"https:\/\/www.rawchili.com\/nba\/746379\/"},"modified":"2026-05-28T17:57:16","modified_gmt":"2026-05-28T17:57:16","slug":"joe-mazzullas-complicated-celtics-tenure-sets-up-defining-2026-27-season-the-lead","status":"publish","type":"post","link":"https:\/\/www.rawchili.com\/nba\/746379\/","title":{"rendered":"Joe Mazzulla\u2019s Complicated Celtics Tenure Sets Up Defining 2026-27 Season \u2013 The Lead"},"content":{"rendered":"

On Tuesday, May 26, Boston Celtics head coach Joe Mazzulla became the youngest<\/a> NBA Coach of the Year winner since Phil Johnson in 1975.<\/p>\n

At just 37 years old, Mazzulla has already built a decorated resume. In 2024, he became the youngest head coach to win the Finals since player-coach Bill Russell<\/a> in 1969. Mazzulla also has the highest regular-season winning percentage in NBA history at 72.6%<\/a>.<\/p>\n

Given those remarkable achievements from just four seasons, Mazzulla\u2019s job security should be unquestioned. Yet after multiple disappointing playoff exits, lingering doubts remain about whether he is the right coach to maximize the championship window of Jayson Tatum<\/a> and Jaylen Brown<\/a>\u2018s primes. <\/p>\n

Gap Year Overachieving Not Enough?<\/p>\n

Stop me if you\u2019ve heard this before: Mazzulla will enter next season under close watch.<\/p>\n

After Boston\u2019s devastating playoff exit in 2025 \u2014\u00a0a second-round loss to the rival New York Knicks that also saw Tatum suffer a torn Achilles \u2014 the Celtics stripped down their roster and payroll. Several Hall of Fame-level contributors departed, and with Tatum expected to miss the entire 2025-26 season, Mazzulla suddenly had an opportunity to prove himself without overwhelming star talent.<\/p>\n

A 56-win season in a transition year where expectations were modest should have silenced the criticism. Instead, it only complicated the conversation.<\/p>\n

Mazzulla\u2019s Coach of the Year campaign featured innovation, player development, and dramatic in-season improvement. <\/p>\n

It’s still crazy how well the Celtics improved their rebounding throughout the season<\/p>\n

Their DREB% by month, and where it ranked in the NBA:<\/p>\n

Oct: 64.7 (28th)
Nov: 67.0 (26th)
Dec: 68.3 (18th)
Jan: 71.7 (9th)
Feb: 74.2 (2nd)
Mar: 75.7 (2nd)<\/p>\n

Something only a COTY could pull off pic.twitter.com\/qC0dQCSSI2<\/a><\/p>\n

\u2014 SleeperCeltics (@SleeperCeltics) April 16, 2026<\/a><\/p>\n

However, Boston\u2019s third disappointing playoff exit in four seasons \u2014 particularly after blowing a 3-1 series lead to the Philadelphia 76ers \u2014 reignited concerns about his adaptability in the postseason.<\/p>\n

In almost any other context, a championship and historic regular-season success across four years would represent an unquestioned success story.<\/p>\n

But the standard surrounding the Celtics is different. With two homegrown superstars in their primes, the bar for success is high. The lows of Mazzulla\u2019s tenure have been impossible to ignore.<\/p>\n

Playoff Shortcomings<\/p>\n

Mazzulla\u2019s Celtics have taken the \u201cchampionship or bust\u201d idea to heart.<\/p>\n

Their 2024 playoff run was one of the most dominant in NBA history. Since the league adopted its current four-round, best-of-seven playoff format, only two teams have lost three or fewer games during a championship run: the 2024 Celtics and the 2017 Golden State Warriors. Boston won 10 consecutive playoff games on its way to the Finals and never trailed in a series.<\/p>\n

Winning a championship at such a young age is an extraordinary accomplishment for Mazzulla. Two years later, at 37, Mazzulla is the same age as Hall of Fame coach Pat Riley was when Riley won his first of five championships.<\/p>\n

At the same time, failing to win a championship with a roster as talented as the 2024 core would have been viewed as a massive disappointment. And outside that championship season, the Celtics have repeatedly fallen short in series in which they entered as overwhelming favorites.<\/p>\n

\"\"<\/p>\n

Sources for series odds in 2023<\/a>, 2025<\/a>, and 2026<\/a><\/p>\n

Difference Between Regular Season and Playoff Coaching<\/p>\n

Mazzulla has consistently proven himself to be an elite regular-season coach.<\/p>\n

The NBA\u2019s 82-game regular season can be grueling, especially for teams with championship aspirations. Maintaining urgency for seven straight months can be difficult when everyone understands the true evaluation begins in April.<\/p>\n

With Boston\u2019s pedigree as a championship contender, they could have plummeted this season with the baked-in excuses. Instead, they played with relentless energy and focus. The team\u2019s buy-in to Mazzulla\u2019s system never wavered, even as he constantly tinkered with minutes and roles across the roster.<\/p>\n

Even in previous years when the Celtics had greater collective roster talent, their consistency never lapsed. During the 2024-25 season, Boston clinched the Eastern Conference\u2019s No. 1 seed with 11 games remaining<\/a> despite missing a combined 81 games from Brown, Al Horford<\/a>, and Kristaps Porzi\u0146\u0123is<\/a>.<\/p>\n

Mazzulla\u2019s offensive philosophies have been devastating over the course of 82-game regular seasons. Without the do-or-die nature of the playoffs, the math behind high-volume, high-quality three-point looks is a problem opposing teams haven\u2019t found an answer for. <\/p>\n

However, in a seven-game series, the Celtics can\u2019t afford to be so patient in their process. Shooting variance becomes magnified in the playoffs.<\/p>\n

Poor shooting luck has haunted Boston in its past two playoff exits, but the inability to find a counterpunch is not an excuse. Mazzulla\u2019s lack of adjustments has become a weak point.<\/p>\n

What Are the Adjustments?<\/p>\n

This season\u2019s roster featured a wide range of complementary skill sets from a rotation as deep as Mazzulla has had yet. But for all of the innovation during the regular season, the Celtics went down without much creativity.<\/p>\n

Rotations shrink in the playoffs as the margin for error decreases. Still, in 48-minute games when the Celtics\u2019 process looked gummed up, Mazzulla could\u2019ve leaned more on chaos-causers like Jordan Walsh<\/a>, Hugo Gonz\u00e1lez<\/a>, or Ron Harper Jr<\/a>., even for short stints to help energize the team. Or even in Game 5 when Boston\u2019s offense scored just 11 points in the fourth quarter and Payton Pritchard<\/a>, who is a proven offensive performer, watched from the sidelines until the game was all but over.<\/p>\n

Beyond the center rotation, which was a losing equation for the Celtics regardless of how Mazzulla deployed it, the lineup innovation that made the regular season so special was gone. That was, until Game 7, when he threw out a starting lineup that played zero minutes together all season.\u00a0<\/p>\n

Tonight’s Celtics starting 5 (trigger warning):<\/p>\n

Derrick White
RON HARPER JR
BAYLOR SCHEIERMAN
Jaylen Brown
LUKA GARZA<\/p>\n

This lineup hasn’t played a single minute together all season<\/p>\n

I dare the 76ers to sleep on this group pic.twitter.com\/JF9eucR33X<\/a><\/p>\n

\u2014 SleeperCeltics (@SleeperCeltics) May 2, 2026<\/a><\/p>\n

Learning Lessons<\/p>\n

Ahead of the 2022-23 season, when Mazzulla took over as Celtics interim head coach, Boston had made the playoffs in the previous eight seasons. With Tatum and Brown ascending to perennial All-NBA talents, surrounded by several other high-level contributors, Mazzulla was the one in the locker room who needed the most development.<\/p>\n

Mazzulla is still young and clearly has a phenomenal feel for the modern game of basketball. The clock is ticking for Mazzulla to figure it out, though. Tatum and Brown are too talented to waste their primes on a hypothetical great coach.<\/p>\n

If he can improve his feel for postseason adjustments, the Celtics have a stellar combination of basketball minds in Mazzulla and Brad Stevens, their president of basketball operations, for years to come.<\/p>\n