It will likely be even more difficult for the Bruins to submit a lineup without Chara's name for Game 5 against the St. Louis Blues at TD Garden on Thursday (8 p.m. ET; NBC, CBC, SN, TVAS) with the best-of-7 series tied, not just because of what the 42-year-old means to the Bruins and the defense, but also because of what he means to Cassidy and the players.
"It was tough for me between periods, when we were told he wouldn't be able to play, because he wants to play," Cassidy said Wednesday. "If he was given the green light, no matter what the severity was, he'd be out there. We know that about [Chara].
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"But the mindset the players put themselves in, in terms of putting pressure on themselves, I think players do that. They know that more is required. Not a lot. I think if everybody does a little bit more -- not one particular player, that's what we're trying to avoid, that one guy doesn't go in and say, 'I've got to be a hero.'
"I think it falls on the whole team."
Chara has not officially been ruled out for Game 5 with what Cassidy called a facial injury but appears unlikely to play. It seems more likely that defenseman Matt Grzelcyk will play, though he remains in concussion protocol after missing Games 3 and 4 because of a hit by Oskar Sundqvist in Game 2 that earned the Blues forward a one-game suspension.
Grzelcyk, who has yet to be cleared by doctors, practiced with the Bruins in a red non-contact jersey Wednesday.
"He gets cleared, he'll be ready to go," Cassidy said. "Whether that's by tomorrow or not, can't tell you."
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Grzelcyk seemed heartened by being able to skate, even if there are no guarantees for Game 5 and beyond.
"I'm feeling good," Grzelcyk said. "It's obviously nice to join back with the team and get out there and take some reps on the ice. … I think the toughest thing was just not being out there with the team. I'm just happy to be back, around the guys. I feel a lot more like myself. Hopefully I get cleared to play."
As for Chara, Cassidy said he had not seen or spoken with the Bruins captain, who was not at TD Garden on Wednesday, but that he had texted with him.
What did he say?
"Not much," Cassidy said.
At practice Wednesday, the Bruins used Steven Kampfer on the third defense pair, lining him up with Connor Clifton. The fourth pair was Grzelcyk and Urho Vaakanainen, the Finland-born prospect who played in his first two NHL games in October before sustaining his own concussion. He spent the rest of the season with Providence of the American Hockey League and played his most recent game in the Calder Cup Playoffs on April 26.
So, as Cassidy said, it would be a "big ask. A real big ask" for Vaakanainen to step into Game 5 of the Stanley Cup Final.
"If that's the way we've got to go, then that's the ask we're going to make," Cassidy said. "But right now, that's a longshot to go that way, especially seeing [Grzelcyk] out there today. That gives us all a little bit of confidence that he's closer. It's always a step in the protocol to get out on the ice."
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The Bruins could still use a lineup with 11 forwards and seven defensemen if Grzelcyk is able to return, adding Kampfer to the lineup to help protect him. Or they could go with six defensemen, using Kampfer on his weak side with Clifton, if Grzelcyk remains unavailable.
But it would be tough to play Vaakanainen.
"I don't know about the inexperience," Cassidy said. "It's just the stage we're in now. We're in Game 5, this type of series. Earlier in the playoffs, maybe a little different for a guy to get acclimated. But we're so far along now, it would be difficult. You're almost to the point where maybe just ask guys to play more minutes at this point."
Some of what they might ask of the players includes more offense from the forwards, more discipline from the team, more of what they can provide without being tasked with being Chara or Grzelcyk -- or changing what they do best.
That, Cassidy believes, would be the best approach, given the circumstances.
"When you lose your captain, the last game, you try to step up and be good for him," Bruins center Patrice Bergeron said. "It's the same thing right now. We're all behind each other and all supportive of each other, and that's why we're here."
And though it would not be easy for Cassidy to remake the lineup and leave Chara sitting in the press box, to upend what he has worked to create this season, it's not like he hasn't done it before. The regular season rarely saw the same six defensemen play together for any lengthy stretch -- no defenseman played more than Brandon Carlo's 72 games, with Grzelcyk next on the list at 66 -- and the Bruins were without Chara (undisclosed injury) in Game 4 of the Eastern Conference Final and defenseman Charlie McAvoy (suspension) for Game 1 of the conference final.
So he knows the Bruins have done it.
"I think our guys are good that way, knowing that the team will pull together," Cassidy said. "Just tough when you lose [Chara]. He is your captain. He plays some valuable minutes. And this particular series is against a heavier team, that's where you miss the actual, what he brings to the table.
"But in terms of mentality, I think this team will be OK."
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