BOSTON -- Bruins captain Zdeno Chara was not at TD Garden on Wednesday as the team practiced a day ahead of Game 5 of the Stanley Cup Final -- a likely sign that the defenseman will not be available to play.

The Bruins and the St. Louis Blues are tied at two games apiece, with the series shifting to Boston for Game 5 on Thursday night.

Boston coach Bruce Cassidy said he would provide a game prognosis for Chara on Thursday, saying only that the 6-foot-9 defenseman had a "facial injury."

Multiple reports emerged Tuesday suggesting Chara had a broken jaw after being hit with a deflected puck in the second period of Game 4. He left the game, got stitches and the trainers did not medically clear him to return, although he sat on the bench in the third period because he wanted to be with teammates.

Cassidy said earlier in the week that Chara might need more dental work later on.

The Bruins are considering several contingency plans if Chara is out, and they do have some encouraging news as defenseman Matt Grzelcyk skated Wednesday -- albeit in a red non-contact jersey. It was the first time Grzelcyk has been with the team on the ice since he was concussed in Game 2 on a hit by Blues forward Oskar Sundqvist.

Cassidy said Grzelcyk is still in concussion protocol, though that status could change on Thursday, meaning Grzelcyk could be available to rejoin the lineup.

"When he gets cleared, he'll be ready to go," Cassidy said. "Whether that's tomorrow or not, I couldn't tell you."

Grzelcyk said he was "feeling good" and "it was nice to join back with the team and get some reps on the ice."

Sundqvist was suspended one game by the NHL for the hit. Grzelcyk, speaking for the first time since the incident, declined to give an opinion on the play.

"The league handled the hit, so I'd rather not comment on it," Grzelcyk said.

Rookie defenseman Urho Vaakanainen also practiced with the main group Wednesday, although Cassidy said it was a "long shot" for Vaakanainen to play. The 20-year-old Finn played in only two regular-season games for the Bruins.

"That would be a big ask," Cassidy said, noting that Vaakanainen, who played a majority of the season in the AHL, has not been around the NHL club much. "A real big ask."

Veteran Steven Kampfer is a more likely candidate to plug in on the blue line. He played in two Stanley Cup playoff games this spring -- and he scored a goal while subbing for the suspended Charlie McAvoy in Game 1 of the Eastern Conference finals.

"Whoever comes in, it's kind of a seamless transition," Kampfer said. "I think that's been our identity of our team this year -- next man up and making sure that you're ready to go."

Cassidy had floated the idea of suiting up seven defensemen and only 11 forwards, though that seems less likely now. It would probably only happen if Grzelcyk is medically cleared.

"We're almost at the point where we just ask guys to play more minutes," Cassidy said.

The 42-year-old Chara has a goal and four assists with a plus-12 in 20 playoff games this spring. He typically plays on the top pairing with McAvoy and is an important player on the penalty kill. Chara played over 24 minutes in Games 2 and 3.

Patrice Bergeron said he did not see Chara on Wednesday and has not talked to him. Neither did Cassidy, though the coach said the two texted but would not reveal anything about the exchange.

"Things you can't control, it's important not to let them distract you," Bergeron said. "When players are missing, it's up to the others to raise their game. We will see who will be with us tomorrow and who will not be there. Still, for us, the recipe does not change. Our wins are team wins. This is what we're gonna have to do to be successful."