Carter Rowney is out "long-term," minimally a month, according to coach Mike Sullivan.
The fourth line center suffered an upper body injury in the second period of Tuesday's win at the Flyers. Rowney has two goals and two assists in 27 games this season.
Rowney's absence means that Sullivan will have to juggle his lines around. Most notably, Jake Guentzel will center the third line while Riley Sheahan will center the fourth as he did in Philadelphia.
With Sheahan reunited with Ryan Reaves and Tom Kuhnhackl, and Guentzel between Carl Hagelin and Daniel Sprong, Sullivan said it gives his team some scoring depth.
"We really liked that line when it was together," Sullivan said of Sheahan's line, which produced two goals against the Flyers. "It gives us the ability of playing four lines and use the bench more."
Guentzel played center against Vancouver on Nov. 22, scoring twice on the power play.
"We know he's capable of playing center, he's played the center ice position in the past, he's comfortable playing center," Sullivan said of Guentzel. "That's always an option for us. We've never taken it off the table."
The prognosis is a little better for Brian Dumoulin. He is out day-to-day with a concussion but is making progress, according to Sullivan. Dumoulin, who took a puck to the head in the second period, will miss his first game this season. He has two goals and two assists in 41 games.
With Dumoulin out, Matt Hunwick will draw back into the lineup. Hunwick was a healthy scratch for the first time this season Tuesday at the Flyers.