Celtics Assistant Coach Hires a Success but now Joe Mazzulla Must Grow

Joe Mazzulla and the Boston Celtics began their first full offseason together by adding former Philadelphia 76ers assistant Sam Cassell and Mike Budenholzer’s former associate coach Charles Lee to a bench widely expected to undergo massive change this summer.

Lee will replace Ben Sullivan, widely expected to re-join Ime Udoka in Houston, and Damon Stoudamire before him as Mazzulla’s No. 2 coach. Adrian Wojnarowski first reported the Lee hire, which followed Toronto’s decision to hire Darko Rajaković over finalists that included Lee.

Lee also nearly landed the Detroit Pistons job before the team circled back to Monty Williams with $78-million. Boston reportedly targeted Lee during its head coaching search in 2021, Brad Stevens assessing Udoka, Cassell, Chauncey Billups, Jamahl Mosley, Darvin Ham and others during that coaching cycle. Lee coached from 2014-2018 in Atlanta, overlapping for two seasons with Al Horford, before joining Budenholzer in Milwaukee since 2018, where Ham and Sullivan also coached and won the 2021 NBA championship. He played professionally in Israel, Belgium and Germany after starring at Bucknell from 2002-2006. He’s 39 this season.

Budenholzer named Lee as his top assistant entering the 2022-23 season. They initially crossed paths while Lee unsuccessfully tried out for the Spurs during the summer league before beginning his overseas career. After, Lee joined Dave Paulsen’s Bucknell staff who reached the NCAA Tournament, losing in round one against a Butler team coached by Stevens one year before he took over the Boston Celtics bench he’s now helping fill as president. Mike Muscala, who could return to Boston on a team option this year, played on that Bucknell team.

Along with Sullivan, multiple reports indicated Aaron Miles, Garrett Jackson, Mike Moser and more could depart the Celtics’ bench from the Udoka era, leaving Tony Dobbins and D.J. MacLeay among other development coaches. Boston missed Stoudamire’s former player perspective and tough talk after he departed.

“Just giving me advice,” Marcus Smart told CLNS Media earlier this season. “Things that he sees that I probably wouldn’t be able to see on the court. Things when he played, little tips here and there to make my life and the game easier for me … when you’ve got a guy with his credentials, well respected and knows the game, you kind of tend to listen to him … to be able to get some criticism, constructively. We don’t take it personally. Both ends. If I see some things I don’t like from him, I’m like, ‘hey can we try this? These things.’ We’re very open. That trust right there and that communication allows us to have the relationship that we do.”

Stevens previously tried to replace Udoka’s spot on the staff after his suspension by pursuing his former assistant Jay Larranaga, who remained with the Clippers. Stephen Silas appeared at Boston’s practice facility before the season and joined Williams’ staff in Detroit after the Celtics pursued him again into the offseason. Stevens praised Boston’s staff in his postseason press conference, but Mazzulla undoubtedly lacked some support.

Cassell brings back that player perspective having played from 1993-2009, winning the 2008 title in Boston and playing four seasons alongside Kevin Garnett in Minnesota and on the Celtics. He began coaching in 2009, mostly under Doc Rivers with the Clippers and 76ers until last season. His criticism of James Harden in the playoffs reflects collective accountability the Celtics need to reintroduce after Udoka prioritized it in 2022.

Lee should bring some defensive principles from a Bucks team regularly stressed that end of the ball and overtook the Celtics as the top unit in the NBA this year. They typically guarded with Brook Lopez in drop position and Giannis Antetokounmpo either roaming or guarding the pick-and-roll directly. Their analytical approach of prioritizing opponents take mid-rangers, rarely reach the rim and limiting three-point attempts overlaps well with the path Mazzulla’s staff took toward a No. 2 unit this past year. Finding the right switching attack, increasing turnovers and developing better efforts in isolation remain key to rekindling the team’s 2022 success.

That falls on Mazzulla, who stressed offense from the opening days of training camp and overlooked defensive lapses publicly. By the end of the Philadelphia series, numerous key players expressed a desire to return to the defense-first approach and they rode it to a turnaround down 2-3 against the 76ers. Robert Williams III returned to the starting lineup alongside Horford before exiting it in the Miami series after two games. Boston struggled to develop the offensive variety, defensive intensity and connectedness from the regular season, and rarely utilized bench players like Sam Hauser and Grant Williams who played well in earlier moments.

The Celtics retained Mazzulla, acknowledging the tough position he coached through this year, highlighting his successes and believing in his philosophies. Stevens expressed the same message Mazzulla did for much of the year, Boston’s players succeeded, hit the right marks statistically and a high-ranking defense characterized what’s true. General inconsistency also defined the team, along with a clear inability to learn from lapses that led to losses. Boston typically turned the page after its tough losses and forgot about them until they couldn’t anymore.

“There’s some adversity, there’s some, quote-unquote, failures or losses,” Lee told The Athletic in 2022. “But how are we going to respond to that and how do we just develop this thicker skin to be able to deal with these adverse situations? Then controlling what you can control kind of flows into my coaching philosophy. Daily improvement … the second part, again, competitiveness. I think that if you can compete at a high level physically, but also the mental side of it as well, you’re going to put yourself in a good position to win a lot of games. And then the third part of my philosophy is just togetherness. How can we come together as a team? How can I as the head coach, or even as an assistant coach, build relationships where I’m earning their trust?”

Mazzulla shouldn’t shoulder blame for the Celtics’ players lapsing in areas he stressed throughout the year in ways similar to their past playoff defeat. Lee and Cassell’s presence nonetheless strikes a balance between pushing the young head coach to improve, lapses like the timeout and late possession management in Game 4 against Philadelphia can’t happen again, while also supporting him without forcing him to look over his shoulder.

Neither Cassell nor Lee held head coaching jobs previously, but their candidacy for such roles received high marks across the NBA in recent years. They can begin developing relationships, pushing this roster toward growth and if it eventually becomes necessary, sit in position to take over a roster that undoubtedly failed despite all the circumstances that challenged them in 2023. At some point, it’s not about the coaching, but the Celtics made sure of it with these moves.

“We have a good staff,” Stevens said. “That’s one thing that gets lost in the shuffle, because we had a lot of people we lost, but the staff we had was good … (additions) were to be supplemental, because we believed in the people that were here.”