Hockey is a bruising, physical sport. But even by the game's standards, the Boston Bruins are beat up pretty badly heading into a crucial Game 5 of the Stanley Cup final on Thursday against the St. Louis Blues.

Defenseman Matt Grzelcyk, who is in concussion protocol following a nasty hit in Game 2, practiced with the team Wednesday at TD Garden in a red, non-contact jersey, but hasn't been cleared to play.

And there's no official update on captain Zdeno Chara, who was taken out of Game 4 after he took a puck to the face. Bruins head coach Bruce Cassidy would only say he's dealing with a "facial injury" and that he'd provide a prognosis Thursday.

But Cassidy was in a good mood Wednesday, considering two of his best players aren't guaranteed to be participate. He even cracked a smile as he told reporters he did text with Chara, but that he didn't say much.

In a more serious tone, Cassidy pointed out the Bruins have had key players hurt ahead of key games before. And while he admitted Chara has played valuable minutes against a heavy team like the Blues, Cassidy said the mentality of the team should be OK.

"We don't know if [Chara], if he misses one game, if he wouldn't be available for the next one," he said. "If that's that case either, we don't really know right now. So there's a little bit of that hope factor for us as well."

Chara didn't practice, but Grzelcyk seemed relieved to get back on the ice after missing Games 3 and 4.

"I think just the toughest thing is just not being out there with the team," Grzelcyk said. "You know, having to sit and watch is obviously tough when you get to this stage. So, I'm just happy to be back around the guys, kind of feel a lot more like myself and, yeah, hopefully I'll get cleared to play and if I get called, I'll be ready."

With the series tied at two games apiece, the margin for error for both squads is razor thin and only getting smaller.

And in a series where the pendulum of momentum seems to swing from team to team after each game, it's hard to say which squad has the upper hand heading into the final games of the NHL season.

But despite the uncertainty of this series and the injuries Boston is dealing with, center Patrice Bergeron still expressed a calm confidence in the Bruins' chances.

"If someone had said that at the start of of the year, that we're gonna be in the best of three for the Stanley Cup with home ice, I think we would have taken it," Bergeron said. "So, that's the situation we're in. I think we have to look forward and just be ready for Game 5."