Giroux entered Tuesday's games as the NHL's leading scorer with 39 points in 28 games. He also leads the Flyers with 16 goals and 23 points.
The 5-foot-11 forward left Saturday's game against Tampa Bay in the second period and did not return after being hit in the head by the knee of teammate Wayne Simmonds.
Giroux had gone to his knees to make a defensive play in the neutral zone. Simmonds was trailing the play and tried to jump over Giroux, but didn't get high enough, and his knee collided with the right side of Giroux's head.
"Obviously he's a guy you can't replace. It's going to take a lot of people to step up and fill the role that he plays. He does everything for us -- penalty kill, power play, scores big goals, makes big hits, blocks shots … does it all. So we're going to have to kind of step up our game here." -- James van Riemsdyk
The Flyers are getting used to different players stepping into new roles recently. Giroux's injury is just the latest blow to a Flyers team that enters play Tuesday atop the Eastern Conference despite missing prospect Brayden Schenn with a mild concussion, and defensemen Pronger, Andreas Lilja (ankle) and Erik Gustafsson (wrist).
"I think Danny (Briere) has done a nice job and we really need his veteran leadership and his veteran presence on the ice certainly with the absence of Claude," said Flyers coach Peter Laviolette. "When Chris Pronger goes out we look for the other big horses on the back end to pick up more valuable minutes and we look to those kids (rookies Marc-Andre Bourdon and Kevin Marshall). I think the same holds true for Claude. When he goes out we look for the veteran players like Danny to step in and we also look at the young players like Matt Read or Sean Couturier to pick up the slack."
The Flyers have gone 10-4-1 while Pronger has been sidelined this season with eye, knee and head injuries, but replacing Giroux presents a new set of challenges.
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The Flyers are 17-3-1 when Giroux records at least one point; 1-4-2 when he doesn't.
"All teams wonder what happens when you're down, what happens when things are bad and what happens when guys are missing," said left wing Jody Shelley, who is expected to dress for Tuesday's game against the Capitals after being a healthy scratch in Philadelphia's last five games. "We haven't spent any time talking or thinking about it as far as Pronger and now (Giroux) … It's just a test of our system and our young energy, I guess. It's almost like an ignorance to even spend time looking at that. We just stay focused; we're in Washington with a game. The 20 guys that are wearing the Philadelphia Flyers jerseys are representing the organization, and we play one way and we're going to do it again tonight."
Giroux has spent much of the season centering Jaromir Jagr and Scott Hartnell on Philadelphia's No. 1 line and he leads all Flyers forwards with an average of 21:28 of ice time per game.
Among those expected to help fill the void left by Giroux is 19-year-old rookie Sean Couturier, who took Giroux's spot for the latter part of Saturday's win against the Lightning and did not look out of place. He had been centering the fourth line.
"Sean has played extremely well for us this year in any role that we've given him," Laviolette said. "He's a real smart hockey player, he thinks the game really well, defensively he's been excellent and offensively there's a lot of potential there."
"I'll try to use my size and my creativity in the offensive zone," Couturier said of joining Jagr and Hartnell on the top line. "They're two great guys so it should be easy to adapt for me … just have to work hard and get to the net and good things should happen."
The eighth pick of the 2011 Entry Draft, Couturier is second among Flyers forwards and second among all NHL rookies in average shorthanded ice time per game.
Couturier acknowledged this morning that his play away from the puck went a long way in helping him secure a full-time NHL job months after being drafted. Now the former QMJHL scoring champion will rely on his offensive instincts as he tries to stick on Philadelphia's top line for however long is needed.
"We don't sit here and look for a crutch or a hole and think we're going to sit back on it," Shelly said. "There are guys from the first moment in camp, we've all been like, 'Wow, where'd this guy come from?' We have a situation, I think, too, where you got guys that are waiting to jump in a spot and show what they got. You look at Couturier. He's been waiting on the fourth line -- he's a great talent, he's done a great job. And now he's getting an opportunity. I think we're all excited for those situations and to see how they play out."