He's spent the past year trying to find those missing parts, and he's confident that with his roster makeover, his team will have more success against the Philadelphia Flyers when the rematch of last year's historic conference semifinal starts Saturday in Philadelphia (3 p.m. ET, NBC, CBC, RDS).
Of the 20 players who dressed for the Bruins in that fateful Game 7 last May, there will be seven new faces in the lineup (plus center David Krejci, who missed the final four games of the series with a broken wrist, and defenseman Dennis Seidenberg, who missed the playoffs with an arm injury).
Chiarelli said changing the makeup of the locker room following the difficult loss "wasn't the sole driving force to the player moves," but that some of the things he saw in that series last season weren't positive.
"Certainly you look at some performances in that series and place a certain amount of weight on those performances and make your decisions. Maybe subconsciously it was driving us."
-- Peter Chiarelli
Over the summer Chiarelli chose to allow forwards Miroslav Satan and Steve Begin to leave in free agency, and forward Vladimir Sobotka was dealt to the St. Louis Blues. Those moves allowed rookie Brad Marchand to earn a full-time job this season.
The biggest summer move, however, was dealing defenseman Dennis Wideman and a pair of draft picks to the Florida Panthers for forwards Nathan Horton and Gregory Campbell.
Horton, in his first Stanley Cup Playoff series, scored 3 goals, including the series-clinching overtime goal in Game 7 Wednesday against the Montreal Canadiens.
"I think Nathan's had a strong playoff," Chiarelli said. "Obviously he's got some timely goals. I see him getting a little bit more comfortable shooting the puck, especially when he scored the one-timer (in Game 7). He just released better, and he's getting more activated with that."
He kept tinkering during the season, trading Matt Hunwick to Colorado to open more playing time for Adam McQuaid. Then at the trade deadline he did his biggest work, acquiring forward Chris Kelly from Ottawa and defenseman Tomas Kaberle from Toronto for draft picks and prospects, and then sending forward Blake Wheeler and defenseman Mark Stuart to Atlanta for forward Rich Peverley.
Kelly, regarded more for his defensive prowess, led the Bruins in scoring in the first round with 6 points. He also moved from center to the wing and never missed a beat.
"He's just a very smart player," Chiarelli said. "He fills lanes. He doesn't make sexy plays, he makes good plays, strong plays. … He senses trouble defensively and he knows what he's doing and he doesn't panic. He gets his nose in there, so he gets his nose in all three zones. You saw how he scored. I've seen him score nicer goals, but those are the goals we expect from Chris Kelly. He has some speed, he's a very versatile player that can play center, good in faceoffs, good on the penalty kill. He's a good, solid two-way payer. And he's a good character kid. He's been around the block a little bit and he knows what to expect and he'll tell guys how he feels."
The chemistry Kelly and Peverley formed also was a big reason the Bruins were able to advance past the Canadiens. Those two, along with Michael Ryder, combined for 6 goals and 8 assists in the seven games, and were a combined plus-10.
"When we acquired those guys we put them in on the third line, that's how we projected the lineup," Chiarelli said. "I think it's switched over the course of the end of the regular season … we had it flipped around. We had Peverley on the wing, Kelly in the middle, but we knew both could switch so we had that flexibility."
Chiarelli said the poise he saw from his team in its hard-fought first-round series with the Canadiens could be a byproduct of the roster turnover.
"We earned three overtime games and we won those three," Chiarelli said. "That's the highest pressure point in the playoffs, and we managed to win those three. And then I saw times when we had some defensive breakdowns, I saw us settle it … and not panic. But it's not that we didn't panic at all, or some of the time, but we just settled the pucks down and we made the right pass where there was a (pass) to a center seam or something, and then we broke out fine. So I just saw that growing a bit as the series went on. And you look to have that, and I hope we continue to have that."
Contact Adam Kimelman at email@example.com. Follow him on Twitter: @NHLAdamK