Being the head coach of professional sports teams in Boston is only a fraternity for a select few at a time.

That group lost one of its members on Tuesday.

The Bruins decided it was time to acquire Jim Montgomery after an 8-9-3 start to the season. They promoted Joe Sacco to interim head coach.

Montgomery’s departure drew a response from another Boston head coach when Joe Mazzulla addressed Montgomery’s firing before the Celtics took on the Cleveland Cavaliers at TD Garden.

“I spoke to him a few times. It is difficult,” Mazzulla told reporters. “I’ve talked to him a few times and I enjoyed watching the games, but I haven’t really delved deep into his coaching philosophy or things like that. “I hate to see any coach have to go through this, but we’re all hired to be fired.”

Montgomery spent more than two seasons at the helm of the Bruins, amassing a 120-41-23 record, including presiding over the winningest season in NHL history as the Bruins racked up 65 wins during the 2022-2023 season.

But that wasn’t enough to save Montgomery’s job. Boston’s shortcomings in the playoffs under Montgomery — the Bruins went 9-11 the past two seasons and didn’t advance past the second round — ultimately affected the 55-year-old as well.

Mazzulla became head coach in Boston at the same time as Montgomery, but under completely different circumstances. Montgomery’s stint with the Bruins was a second chance after being let go by the Dallas Stars midway through his second season in charge. Mazzulla was named interim head coach of the Celtics just days prior to the team’s 2022 training camp, following the Ime Udoka saga.

Mazzulla is now the second-longest active coach in Boston’s professional sports scene, behind Alex Cora, who signed a three-year contract extension this season to remain with the Red Sox and has led the club for six seasons. Jerod Mayo, who is off to a 3-8 start in his first season as head coach of the New England Patriots, is now third on that list.