Galchenyuk was injured during a 5-4 shootout win at the Los Angeles Kings on Sunday when he collided with Kings center Anze Kopitar in the offensive zone past the midway point of the second period. Galchenyuk appeared to be favoring his right leg after it was clipped by Kopitar's leg.

Galchenyuk leads the Canadiens with 23 points (nine goals, 14 assists) in 25 games this season. His position as the top-line center between Max Pacioretty and Alexander Radulov was filled the next game by Desharnais, who did not make it through that 3-2 overtime loss at the St. Louis Blues on Tuesday, leaving the game in the third period. Desharnais has three goals and nine points in 25 games.

This is the second season a row the Canadiens lost key players for an extended period of time. Last season, goalie Carey Price sustained a season-ending knee injury on Nov. 25.

"Every team has to deal with injuries at some point," Canadiens right wing Brendan Gallagher said Tuesday before playing the Blues. "We've learned a lot of lessons like that in the past. We're capable of doing it. [Galchenyuk] is obviously a very good player. You can't replace him, but I think if everyone steps up and does a little bit more, we can certainly still find ways to win hockey games. That's all that matters."

The Canadiens have Tomas Plekanec and Torrey Mitchell as centers on the roster, and forwards Andrew Shaw, Phillip Danault and Brian Flynn have experience playing there.

"We've had to face adversity before in years past," captain Max Pacioretty said Tuesday before the game when Desharnais was injured. "Obviously [Galchenyuk] is a big part of this team, but I think when a guy like that goes out, it's a big opportunity for other guys to step up and fill the role."

The Canadiens called up forward Sven Andrighetto from St. John's of the American Hockey League and sent down defenseman Mark Barberio and forward Charles Hudon on Wednesday. Andrighetto has not played center at the professional level, but Hudon is a natural center who was switched to the wing by the Canadiens when he turned pro in 2014-15.

Andrighetto has no points in four games with Montreal this season and 20 points (seven goals) in 18 games with St. John's. Hudon has two assists in three games with Montreal and 14 points (nine goals) with St. John's.

Barberio being sent down would suggest that defenseman Nathan Beaulieu might be ready to return from a throat injury he sustained when he was hit by a puck against the Ottawa Senators on Nov. 22. Beaulieu has missed six games.

The Canadiens host the New Jersey Devils at Bell Centre on Thursday (7:30 p.m. ET; SN360, RDS, MSG+ 2, NHL.TV).