The Boston Bruins have fired coach Jim Montgomery team announced on Tuesday. Assistant coach Joe Sacco will take over on an interim basis.

The Bruins are 8-9-3 and hold the No. 2 wild-card spot in the Eastern Conference. They are coming off a 5-1 loss to the Columbus Blue Jackets on Monday with a goal differential of minus 21, second-worst in the league. Only the Pittsburgh Penguins’ minus-25 is lower.

Montgomery, the 2023 Jack Adams Award winner as the NHL’s top coach, was in the final season of a three-year contract. He completes his Bruins run with a record of 120-41-23. In 2022-2023, the Bruins lost to the Florida Panthers in the first round after winning an NHL record 65 games. Last season they lost to the Panthers in Round 2.

This season, the Bruins have had all kinds of problems under Montgomery. They laid a 6-4 egg against the Panthers in the season opener. They have since discussed the shortcomings. They have the worst power play in the league (11.7 percent). Their penalty kill is No. 25 (75.6 percent). They have taken a league-high 101 penalties. They have scored 31 five-a-side goals, more than just five clubs.

David Pastrnak (17 points from 20 games) is improving after a sputtering start. He doesn’t have much company. Jeremy Swayman, who missed all of training camp before signing his $66 million contract, has an .884 save percentage. Brad Marchand, Charlie Coyle and Morgan Geekie, who started the season as runners-up, each have one five-on-five goal.

Did Montgomery deserve to be fired?

Whether this is all on Montgomery is doubtful.

Hampus Lindholm, the Bruins’ best player this season, has been out for weeks after blocking a shot against the St. Louis Blues on Nov. 12.

So far, it appears general manager Don Sweeney has been thumbing his nose at Elias Lindholm ($7.75 million average annual value) and Nikita Zadorov ($5 million), his two most important offseason acquisitions. Max Jones, also a summer signing, was assigned to AHL Providence after just four games. Sweeney has been busy with his national duties for Team Canada ahead of the 4 Nations Cup.

The team is also paying the price for depleted futures. Mason Lohrei is struggling defensively. The Bruins assigned Matt Poitras, once considered the No. 3 center, to Providence. Georgii Merkulov, the Bruins’ 24-year-old center, has spent the past two games at third on the left wing. Jordan Oesterle and Jeffrey Viel, two depth players, have currently been recalled by the AHL.

But Montgomery had 20 games to find answers since the season opener. With no end in sight to the tires spinning, the Bruins had no choice but to make the move.

What you need to know about Sacco

Sacco was promoted to associate coach before the season. He has been on the Bruins staff since July 24, 2014, as an assistant for Montgomery and former head coaches Bruce Cassidy and Claude Julien.

Sacco, a native of Melrose, has head coaching experience with the Colorado Avalanche, where he went 130-134-30 in four seasons from 2009 to 2013. The 55-year-old was also an assistant with the Buffalo Sabres. He played 738 NHL games, mostly for the Mighty Ducks of Anaheim and the Washington Capitals.

Sacco was most recently in charge of the penalty kill for the Bruins.

Required reading

(Photo: Michael Reaves/Getty Images)