Wednesday, Bruins GM Don Sweeney made the announcement.

Thursday morning, it became official.

“The Bruins are very excited to be naming Bruce Cassidy the 28th head coach of the Boston Bruins,” Sweeney said as his opening comment – and seated next to Cassidy. “Despite the season abruptly ending on Sunday [in Game 6 against Ottawa], I felt very comfortable moving forward quickly to name Bruce the head coach.”

Cassidy made it quite clear Sunday about his interest with his final three words when asked if he wanted to return.

“Absolutely,” he concluded, “100 percent.”

“I think that the way our team responded to his message – we had an aggressive bent to our game,” the GM said as he framed his primary reasons. “We scored more goals, we didn’t lose defensive structure and our foundation, our penalty kill remained to be top in the league, and our power play got better as the season went along. To me, it spoke to the change that our team responded to, that our core players responded to, and our young players responded to.”

Not to mention getting the team to its first playoff appearance in three years with the NHL’s best record over 33 games since Cassidy replaced Claude Julien on February 7.

Or coming within a puck-width of advancing to the second round after six one-goal games and four OT affairs against the Senators with a depleted defense and absent David Krejci for most of the series.

Don Sweeney accomplished his first order of business this week by promoting Bruce Cassidy to full-time head coach. (Photo by Angela Spagna, Bruins Daily)

“I’d like to thank the Jacobs family, Cam Neely, and Don Sweeney for giving me this opportunity to continue a proud tradition here to coach an Original Six franchise,” Cassidy said. “I’ve made no secret that I grew up adoring this team and I’m very proud, honored, and privileged to be a part of it, and to be named the head coach.”

“We didn’t get the job done, and we have work to do,” Sweeney said.

That includes in no certain order: decisions about returning Unrestricted Free Agents and extending contracts to Restricted Free Agents, starting with David Pastrnak. Then comes the Expansion Draft to stock the new Vegas Golden Knights team to whom the Bruins will lose one starting player from the current roster, excluding some categories like no-trade clauses and entry-level contracts. All that followed by the Entry Draft in late June. July 1 starts the free-agent frenzy; along the way signing possible NCAA draft picks and other possible amateur-pool pluckings.

Starting with Notre Dame’s talented Anders Bjork.

“We’ll continue to have discussions,” Sweeney said about the prized B’s draftee. “He hasn’t made a firm decision, whether or not he’s leaving school. The opportunity is there for him to join us, and we’d like him to, but again, that’s his decision to make, at the right time.”

Look for Bjork, a possible 2018 Hobey Baker winner, to return for his senior year.

Major work on the ice?

“We want to become a deeper, more talented team from top to bottom,” Sweeney said.

“We have work to do in a lot of areas that we want to continue to get better. I think that the middle part of our lineup, the consistency, scoring, and depth, I think is an area. Transitional puck play is an area that we’re going to continue to look at through personnel, whether that’s internally or outside. The backup goaltender situation was certainly a challenge the first part of the year. Give Anton [Khudobin] a lot of credit. Give Bruce a lot of credit for putting him in and trusting him as well. But, it put a lot of strain on us earlier in the year.”

“We’ve got some Stanley Cup champions in that room,” Cassidy said, “and it showed with high character players and I was very thankful for that. From there, we’re trying to build something together now. That’s the process going forward.”

“[The onus], it’s on right here, right in this chair,” Sweeney added. “But today, I’m very excited to be sitting with Bruce and moving forward with him as our head coach.”

Next Tuesday, the brass — team owner Jeremy Jacobs, CEO Charlie Jacobs and President Cam Neely — hold their press conference at TD Garden to meld the official closure of the 2016-17 season with the look forward to the next.