ST. LOUIS -- The Bruins could be without captain Zdeno Chara for Game 5 after the defenseman took a puck to the face during Boston's 4-2 loss to the St. Louis Blues in Game 4 of the Stanley Cup Final on Monday night.

The incident occurred in the second period. A shot from Blues forward Brayden Schenn deflected off a stick and struck Chara in the face. The 42-year-old defenseman bled profusely, and blood needed to be cleaned up on the ice as Chara was helped to the locker room.

Bruins coach Bruce Cassidy said Chara had some stitches and might need some dental work later.

Cassidy said the training staff advised him that Chara should be done for the night, though he was OK'd to sit on the bench in the third period because he wanted to be with his teammates.

"That's the type of guy he is, come out and be there to support," said Bruins forward Charlie Coyle. "You never want to see that happen to anyone, especially someone on your team, someone who is such a big part of our team playing-wise, leadership-wise. It's not an ideal situation, but it's how you respond to adversity, and you see a lot of it during this time of year."

Cassidy said Chara will be re-evaluated when the team returns to Boston.

"I can't say whether he would play in Game 5 or not, I have no idea," Cassidy said.

Game 5 is set for Thursday night in Boston. The series is tied at two games apiece.

This isn't the first time Chara has dealt with an injury this postseason. The 6-foot-9 defenseman missed the clinching Game 4 of the Eastern Conference finals with an undisclosed injury, but he put on his uniform and skates to join his teammates in the customary handshake line following the contest.

Chara returned to the lineup for the Stanley Cup Final after the team had a 10-day layoff between series.

Chara also sustained an injury toward the end of Game 1 of the Stanley Cup Final. Chara blocked a shot from Vladimir Tarasenko that injured his wrist. Chara, however, said it was just a cut, and he returned to the lineup.

"He's a guy who wants to be out there," said Bruins center David Backes. "He wants to battle and be with the guys. ... If there's any chance for him to be back, he'll be back. If not, it'll be next man up again. Whoever our next guy up is will have to fill that role admirably -- and they're big feet to fill."

The Bruins already are without one for their top six defensemen; Matt Grzelcyk is in the concussion protocol after being boarded by Oskar Sundqvist in Game 2. Grzelcyk has not played since, though earlier Monday, Cassidy said he is "better than he was" and is a candidate to return at some point in this series.

If Chara cannot go for Game 5, the Bruins have several replacement options. Cassidy said the obvious choice would be veteran Steven Kampfer because he has Stanley Cup playoffs experience. Kampfer played one game in the first round against the Toronto Maple Leafs and one game in the Eastern Conference finals against the Carolina Hurricanes, tallying one goal.

However, Kampfer is a right-shot defenseman, and Chara is a left. That means the team also will consider 20-year-old Urho Vaakanainen (two games in the regular season) or 22-year-old Jeremy Lauzon (16 games in the regular season).