But they may have lost even more as both center Patrice Bergeron and defenseman Joe Corvo suffered undisclosed injuries during the course of Game 5.
Corvo was hurt blocking a Marcus Johansson shot midway through the second period, while Bergeron was injured later and missed most of the third period.
There was no immediate update on their condition after the game, but they won’t have much time to heal — the Bruins face elimination in Game 6 in Washington on Sunday.
"Those two guys are being looked at right now," coach Claude Julien said. "So there’s no update on them."
Corvo went down in pain after taking a Johansson shot off his right leg, but play continued and he had to try to hobble back into action on one leg and with no stick. The Capitals eventually took advantage, and Alexander Semin scored the game's first goal, leaving the Bruins down one and Julien irate that play was not stopped for the injury.
"That was the frustrating part for me," Julien said. "When we were in Washington for the last game, twice they had players go down in their own end, and we had full control of the puck, and the whistle was blown right away with no hesitation. And tonight they decided they're not. So, I was a little perturbed. Is there two sets of rules or one? I know they're different referees, but it's still the same series. That was frustrating because they ended up scoring a goal on that."
Corvo was helped to the locker room. He later returned to the bench but did not play another shift. If he is unable to go on Sunday, Mike Mottau will likely make his postseason debut with the Bruins, who are already down one defenseman with Adam McQuaid sidelined all series with an upper-body injury.
Boston nearly lost another blueliner when Zdeno Chara was shaken up at the end of the opening period after being elbowed in the head by Jason Chimera. No penalty was called, and play continued in that instance as well despite Chara being down and dazed. Chara said he was fine after the game, but the fact that the referees allowed play to continue in that instance may have been part of the reason Corvo tried to get back into the play despite his obvious injury.
"The guy's down, he's hurt, and there's no whistle," Julien said. "So he's trying to get up. That's supposedly the referee's discretion. The other night they felt that a quick whistle was the thing to do, and tonight they didn't on both occasions. It's an elbow to the back of the head and that goes uncalled."
Bergeron wasn't as fortunate. He missed most of the third period, returning only for three quick shifts before shutting it down for the day. His status for Sunday is not certain, as was the exact point he was injured. He was on the receiving end of a big hit from Alex Ovechkin but may have already been dinged up at that point.
What is certain is that losing Bergeron for any length of time would be a huge blow to the Bruins.
"You don't want to see anyone get injured," Bruins forward Benoit Pouliot said. "When you get a guy like Bergy out, it's tough. He's our best draw guy and one of our best offensive and defensive guys. You don't want to see Bergy go out, but sometimes you've just got to and the other guys got to pick it up. We did that for most of the third period. It was just a bad bounce at the end."
The Bruins did rally to tie the game in the third without Bergeron and Corvo, but they couldn't overcome a late power-play goal by the Caps after a controversial slashing call on Pouliot.
"He's obviously a big player for our team, but we still did a good job," Bruins forward Brad Marchand said of Bergeron. "We found a way to continue to put pressure on, and we have to do that. It's playoff time. No excuses.”
Marchand was less understanding of the officials' decision to allow play to continue when Corvo went down.
"When a guy's hurt and down like that, I don't know how long he has to stay down before they blow it," Marchand said. "Any time a guy was down for two seconds last game they would blow it. They've got to see that a guy is hurt like that and blow it. But it's great that he showed that effort to get up and try to finish the shift."
Now the Bruins, possibly without Bergeron and Corvo, will need a great effort on Sunday to avoid an early finish to their season.