Injuries to defensemen are inevitable. They’re the ones blocking the most shots. They’re the ones on the receiving end of opposing forechecks.
The fact that the Bruins had gone two months without any -- not even of the minor, take-a-night-off variety -- felt like a borderline miracle. Since Derek Forbort returned from a broken hand on Nov. 29, the Bruins have rolled out the same six defensemen for 24 straight games.

Jakub Zboril got into one game on Jan. 7 as Jim Montgomery elected to dress seven D, but he played just 6:47. Those were the only minutes played by a Boston defenseman not named Forbort, Hampus Lindholm, Charlie McAvoy, Brandon Carlo, Matt Grzelcyk or Connor Clifton since Thanksgiving.
That could be about to change. While the Bruins cruised to yet another win Thursday night, beating the New York Rangers 3-1 to improve to 36-5-4, they also lost Carlo to an injury early in the second period.
With the Bruins starting the period on the penalty kill, Carlo stepped in front of a Mika Zibanejad one-timer and took it off the foot or leg. Carlo finished the shift, but was clearly hobbled. He soon departed for the visitor’s dressing room and did not return to the game.
If there’s a reason for optimism, it would be that the Bruins didn’t immediately rule Carlo out. During the second intermission, they announced that he was “unlikely to return” due to a lower-body injury. While Carlo did, in fact, not return, the fact that he was never definitively ruled out could be a sign that the injury wasn’t too, too serious.
Montgomery didn’t have much of an update on Carlo after the game other than to say that the team would be “careful.”
“We’re gonna be careful,” Montgomery said, according to the Bruins’ team website. “We’ve got a real good extra defenseman in Zboril. If he’s not ready to go Sunday, we’ve got the luxury of getting Zboril into games. We’ll see when we get home and we get our doctors on him.”
If Carlo does have to miss any time, it would be the first test of the Bruins’ defense depth in months.
That depth was certainly tested early on this season when McAvoy and Grzelcyk were out to start the year, Carlo missed some time with a concussion, and then Forbort broke his hand. Zboril played 13 games through the first month-plus of the season, Mike Reilly played 10, Anton Stralman got into eight, and even Dan Renouf got one.
But that was a long time ago. What the Bruins could possibly expect from Zboril or anyone else right now is anyone’s guess.
Zboril has at least been practicing and traveling with the team, which is why he’s the natural choice to be the next man up. But again, he’s played just seven minutes since Thanksgiving. Reilly has played more, but in the AHL with Providence. He’s also not an ideal replacement for Carlo stylistically. Both have at least been doing more than Stralman, who not only hasn’t played in two months, but hasn’t even been practicing with either the Bruins or P-Bruins since getting waived on Nov. 28 -- until, interestingly enough, Thursday, when Mark Divver reported that he practiced with Providence.
If there’s any silver lining at all to Carlo missing any time, it’s what Montgomery noted: It would allow at least one of those guys, presumably Zboril, to get some NHL playing time. At some point before the March 3 trade deadline, the Bruins need to decide exactly how they feel about this group. Having a bunch of bodies on the blue line is nice, but it means nothing if you don’t trust them to play come springtime.
None of Zboril, Reilly nor Stralman looked great earlier this season, and it’s hard to imagine they’d instantly look great now after so much time since their last NHL action. That’s not even an indictment of what any of them have or haven’t been doing to stay ready; it’s just the reality of how hard it is to replicate NHL game action and how easy it is to get rusty.
Even if Carlo doesn’t miss any time now, the chances of the Bruins’ six best defensemen all staying healthy between now and whenever their season ends (which they hope will be June) are very slim. The Bruins are going to need to decide if they trust the guys they already have to step into action down the stretch and into the playoffs, or if they need to bring in outside help before March 3.
The Bruins wouldn’t need Zboril or anyone else to be a direct 1-for-1 replacement for Carlo, who has been playing some really good hockey as Lindholm’s partner in the top four and as a top penalty-killer. Clifton, who played really well with Lindholm earlier this season and who also scored a goal Thursday night, will most likely be the one stepping into that role.
But the Bruins do need a seventh defenseman who can at least step in and do a good job in third-pairing minutes while also contributing on the PK. Montgomery has said repeatedly that he likes Zboril, that he trusts him in such a role, and that Zboril hasn’t deserved to sit so much. Well, here’s a potential chance to prove it.
For the first time in two months, the Bruins’ defense depth might actually be put to the test.