Game 5 of the Stanley Cup Final is scheduled for Thursday night between the Boston Bruins and the St. Louis Blues at TD Garden, with the series tied 2-2 after the Blues' 4-2 home win against Boston on Monday night. What can we expect in this critical matchup in Boston?

Here's a little primer in this edition of Stanley Cup Playoffs Daily.

So is Zdeno Chara going to play or what?

That's the 6-foot-9 question looming over Game 5. The Bruins captain broke his jaw -- the team is a calling it a "facial injury" -- when a Brayden Schenn shot deflected off Chara's stick and the puck hit him in the face. He returned to the bench in a full-shield helmet in the third period, but did not play.

The Bruins haven't ruled him out, with coach Bruce Cassidy saying that he'd know more on Thursday morning, but adding after their practice Wednesday: "Obviously Zee's not here, didn't skate, so it makes it a little more difficult for him. I've always said that: The guys that are skating are obviously a little closer."

If anyone is going to come back and play after an injury like that, it's Chara. The question is whether that'll be in Game 5, Game 6 or if at all this series.

If Chara doesn't go, what's the contingency plan?

Two main options. There's Steven Kampfer, a journeyman defenseman who played 35 games with the Bruins in the regular season and two more in the playoffs. But more intriguing is the potential return of Matt Grzelcyk, the defenseman the Bruins lost in Game 2 on that Oskar Sundqvist hit that earned the latter a suspension. Grzelcyk skated in a noncontact jersey Wednesday as he's still in the concussion protocol, but a return to the ice is a good sign. So in theory, the Bruins could replace one injured defenseman with the return of another.

Is Kampfer ready for this?

As he explained to reporters, he's the kind of defenseman who's always on call. Sometimes it's an injury in the previous game, sometimes it's someone feeling ill after lunch. He's always ready. "You've got to move your feet quick. You've got to make the simple play and I think it comes a lot with transition and getting back on it," he said. "They come down hard, they come down fast, and you've got to make sure that you're ready for everything."

Is Urho Vaakanainen an option?

As a last resort. "That was an option if both guys were out, we've kind of went through them all," Cassidy said. "We're getting into a little bit of hearsay or speculation. That would be a big ask. A real big ask."

Chara or no Chara, what's the game plan for the Bruins?

They have to be remarkably better at 5-on-5. The Blues had the shot attempt advantage in every period of Game 4, with a 49-30 overall advantage. The team that has controlled the tempo on the forecheck has won each game. The Bruins are at their best when they're creating offense off the rush, which the Blues have done a good job limiting in the past two games.

But the real key is not to have one-and-done trips into the St. Louis zone. "Getting the puck to the net, getting inside, rebounds. There'll be some rebounds there if we get there if we have traffic. It sounds cliche, but it's the truth," Cassidy said.

What will the Blues try to do?

Another dose of that formula from Game 4: Big hits, big scoring chances at the net and keeping the penalty box empty as they find their rhythm at 5-on-5. "We just gotta keep doing the same thing," Patrick Maroon said. "Our team's not flashy at all. It's north/south. Dumping it in. Wearing teams down. When we don't do that, their defense is effective in moving up in the play. Odd-man rushes. The D can jump higher. When we're doing well, we're limiting their time and space. We're wearing them down. It makes it difficult for the D to jump into the play."

Are the Blues wearing down the Bruins physically?

They think they are when they roll four lines. "I think we can see it throughout games and throughout the series. It's tough minutes to play against our forward lines when they're playing the way they can," Alex Pietrangelo said. "You you can see the momentum we create by our line changes in the offensive zone, we're just using all four lines. If I was a defenseman, that would be tough to defend against."

Speaking of Pietrangelo, he called former teammate and current Bruins forward David Backes "Buffalo Head" on a recent episode of "In The Crease." What's up with that?

"That's an old nickname," he said Wednesday, and said he might it explain its origins "on another day." Cryptic!

Any lineup changes for the Blues?

If appears Robert Bortuzzo will slot in for Joel Edmundson, who has been rather underwhelming this series. Bortuzzo will play with Vince Dunn, who returned in Game 4.

"We've used everybody, that's what you need to do in the playoffs. It's a good competition. I think all the guys realize it," coach Craig Berube said. "You don't have to be happy about it but you still have to be a good teammate and they have been very good that way. It's great to have the depth."

Is there any chance they can stay out of the penalty box again?

Game 4 marked the first time in the series the Blues killed off fewer than four power plays, and the first time they didn't take at least two penalties in the first period. "We learned our lesson enough times to not be giving them four or five power plays a game. That's just something we touched on," forward Jaden Schwartz said. "We did a good job of that throughout the playoffs, but I think in the first few games, we got away a little bit from that. It's something that you want to pay attention to."

How great are the Blues on the road?

Very. The Blues are 6-0 on road when trailing or tied in series this postseason (excluding Game 1s). That's tied for the most such wins in a single postseason all time. The teams that had the most wins without a loss in this situation were the 2002 Red Wings and 2000 Devils, both of whom went on to win the Stanley Cup.

How much do the Bruins need their stars to step up?

Very much. Patrice Bergeron, Brad Marchand, David Pastrnak, David Krejci and Jake DeBrusk have yet to record an even-strength point in the series. (Marchand's goal in Game 1 was an empty-netter.)

"You always want to play the game that's in front of you. I think last game, there was more 5-on-5 and we need to find ways to generate more offensively," Bergeron said.