Cassidy does believe, however, that he has a clear replacement already on the roster.
"I think the obvious choice is Charlie Coyle," Cassidy said following Day 4 of Bruins Development Camp at Warrior Ice Arena. "He's the most familiar with our guys. I'm the most familiar with him. Allow the other guys to fall into place. I know that [Erik] Haula and [Tomas] Nosek prefer to play in the middle. Nick Foligno is more of a guy that will move around so that's probably how it will play out for him.
"Charlie and Taylor Hall - and [Craig] Smith was on that line last year - if Coyle can bring some of what Krech did, it will be a real good line. That's the way we're leaning and we'll see how the other pieces shake out."
Cassidy also mentioned Jack Studnicka, who has been working out furiously on and off the ice throughout the summer at Warrior Ice Arena, as a potential option to solidify a spot in the lineup if he's able to show significant progress entering his third full professional season.
"How does he fit in? Some of that will depend on his growth," said Cassidy. "Didn't get to play a lot of hockey last year, unfortunately; like a lot of young players, missed some time with the COVID restrictions. But he's also in the mix and I know he looks bigger. He's gonna be really pushing for a spot so we have to include him in the mix as well."
With Brad Marchand and Hall locked in as the Bruins top two left wings, Cassidy envisions Jake DeBrusk slotting in on the third line, which could provide the 24-year-old with some lighter matchups as he tries to bounce back from a disappointing 2020-21 season.
"If Jake ends up as third-line left winger, he's not going against top pairs as much as he used to," said Cassidy. "Can you convince him to bring a little bit more in that regard? Then we have some new faces down there that we don't know a lot about so they should be excited to find their place in the lineup."
With several new faces in the mix and the potential for Coyle or Studnicka to jump up in the lineup, Cassidy expects there to be plenty of motivation and enthusiasm throughout the forward group.
"These guys are excited to move up in the lineup. It's opportunity," said Cassidy. "I would think a guy like Charlie Coyle…he'll be excited for that opportunity. Why wouldn't you be? You get some extra minutes, you're moving up in the lineup, a little more ask on the offensive side of things. Taylor Hall comes in and is excited to play. You've got an elite level left winger out there that has scored in this league.
"That's another area that maybe we didn't have before that now is in the fold for the next four years. You're gonna get some offense from Taylor that maybe you weren't getting as much from that position in the past just because of how good Taylor is."
One thing that Cassidy does not expect to change up front: his top trio of Patrice Bergeron, Marchand, and David Pastrnak.
"Bergy will still give us high-end minutes," said Cassidy. "I think we're gonna start with it together. We know what we have there. They're a handful to play against. Let's see how the other guys plays out, more than moving David around. And then as the year goes on, see how the chemistry's developing on the other lines.
"We know the top line has it. If we need to drop David down and move some pieces around then we'll look at that if it makes us a better team."
Ultimately, Cassidy has options as he tries to map out his lines for the upcoming campaign. With the additions of Haula, Foligno, and Nosek up front, Boston's bench boss has a bevy of versatile, responsible forwards capable of playing multiple positions at his disposal.
"We lose David, but we've made enough additions that we should be a solid offensive team," said Cassidy. "That's the exciting part of this year, we have some new people we're going to be relying on and we feel that they're up to the task. But time will tell."