Washington's skilled center was suspended for one game for a match penalty at the end of Game 3 when he cross-checked Boston forward Rich Peverley in the face at the conclusion of Boston's 4-3 win.
The Capitals didn't agree with the call, but their focus now has to turn to coping without their best playmaker for a crucial game in the series. The Bruins can take a commanding 3-1 lead with a victory, or the Capitals can even it at 2-2 before the clubs return to Boston for Game 5.
It will fall upon two players to fill the void left by Backstrom's suspension. Mathieu Perreault will move up to Backstrom's spot between Jason Chimera and Alexander Semin on Washington's second line, while veteran Mike Knuble will move into the lineup after being a healthy scratch for the first three games.
Perreault did not have a point or even a shot in the first three games of the series, but he did have 16-14-30 totals in 64 games in the regular season.
"During the year Matty stepped up for us when Nicky went down and put a good season together," Washington coach Dale Hunter told reporters after his team's practice on Wednesday.
"He's playing well," Hunter added. "He sees the ice well. He's a creative guy who works hard."
The Bruins know that better than anyone. They saw first-hand what Perreault can do when he scored a hat trick against Boston in the clubs' first meeting this season, when the Capitals took a 5-3 win at the Verizon Center.
Perreault has filled in for Backstrom before, as Backstrom missed 40 games with a concussion when he was sidelined until March 31 after being elbowed in the head by Rene Bourque on Jan. 3. That kept Backstrom out of all four regular-season meetings with the Bruins. Washington won three of those, so the Bruins don't have any false sense of security that things will be easy in Game 4 just because Backstrom is out of the lineup.
"We've just got to focus on what we have to do to win a series here and win a game," Bruins coach Claude Julien told reporters in Arlington, Vir., where the Bruins practiced on Wednesday. "They're still a very, very good team, with or without him in the lineup. They've, I think even Dale [Hunter] mentioned they won some games without him, beaten us without him in the lineup. So, that's not going to be an issue, our issue is going to be, again, about us trying to get better as the series moves on."
The Capitals went 18-16-2 without Backstrom during the regular season. They had Knuble in the lineup for most of those games. He played 14 of the final 15 games of the year even after Backstrom returned, putting up 3-3-6 totals in that span. Overall, he managed just 6-12-18 totals in 72 games, a far cry from the 20-plus goals he scored in each of the previous eight seasons with Boston, Philadelphia and Washington.
Still, it was somewhat surprising to see Knuble as the odd man out up front in the first three games, and his size and experience could come in handy for the Caps.
Backstrom's playmaking skills will be missed, but his absence could also be a rallying point for the rest of the Capitals as they try to cope without arguably their second most important player behind Alex Ovechkin.
They will do it without any sympathy from the Bruins. But they also shouldn't count on the Bruins getting overconfident just because the Capitals are without one of their key players.
"It doesn't really change too much," Peverley told reporters in Arlington about Backstrom's absence. "He's obviously a tremendous talent, a great player in the league. But they've played a lot of the year without him and they've done well. So we're kind of looking at it as they're still a great team and we can't really play differently."
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