Not only did they lose the game, 3-2, and their four-game winning streak, but they also lost faith in Tuukka Rask as the team's No. 1 and Johnny Boychuck.
That's okay, though. Future games can be won, winning streaks built up again, Tim Thomas is playing great ahead of Rask and Boychuck can be replaced.
Or can he?
The Rangers' Brandon Dubinsky slashed Boychuck in the first period on Saturday, and while he went to the penalty box, the Bruins' defenseman went to the training room clutching his hand. Later, it was announced he had fractured his forearm, sidelining him for four weeks.
He'll be a noticeable absence. His 20:22 minutes per game is third most on the team, and he's first amongst the Bruins' defensemen in assists and second overall in plus/minus.
His pairing with captain Zdeno Chara has been largely solid at the back, and they've made few mistakes since that first game. Also, they stifled the Washington Capitals (and in particular, Alex Ovechkin), holding them to just two goals in two games.
Of course, some of that is down to the goaltending. Thomas has been shutting teams down, conceding just three goals in his four starts this year (in which the B's are 4-0, unsurprisingly), but for how long can he keep that up?
We saw in the season opener in Prague that the Bruins are capable of terrible, sloppy play at the back. That left Rask badly exposed, and he couldn't cope with it. Without one of your three best defensive players, Thomas and Rask could be left vulnerable more often.
In Boychuck's place, Adam McQuaid—a healthy scratch in the first six games—will likely make his first appearance of the season on Thursday against the Toronto Maple Leafs. He played in 18 regular season and nine playoff games last year.
At practice, McQuaid was on the third line with Matt Hunwick, while Andrew Ference replaced Boychuck on the top line alongside Chara.
Coach Claude Julien has played around with the lines quite a lot in the early going this year, and the players will be able to adjust quickly. However, the defense has been very good so far, and if it starts to regress without Boychuck, the B's could find their form slipping with it.
While their offense has been productive, ranking eighth in the league in goals per game, it won't be able to bail out the defense every night. This is a team, after all, still without Marco Sturm and Marc Savard. It's still October, but already there are three core players watching from the sidelines.
The Bruins hope to have all three back by the end of November; if they can keep up their great run of form until then, they could be one of the best teams in the East.