The Bruins begin their post-Christmas road trip on Saturday at a crossroads.

They have lost four in a row, with the lone “bright spot” being the loser point in a shootout loss to Canucks, a game they should have put away long before it went to extra sessions.

Last we saw the lads, the designated “must-win” game against the Canadiens on Dec. 23 produced an epic third-period meltdown to send them into the break with a lot more questions than they had just 10 days ago.

And to make matters worse, they start the trip off against the hottest team in the NHL. Yes, that’s who the Buffalo Sabres are right now. The Sabres, who have missed the playoffs for 14 straight seasons, have won seven in a row. At the start of the streak, they fired GM Kevyn Adams and replaced him with Jarmo Kekalainen, the former Columbus GM who has set a demanding tone.

Now the Sabres enter Saturday’s game just a point behind the B’s with two games in hand. With games in Calgary, Edmonton, Vancouver and Seattle to follow – and with Boston a lackluster 8-9 on the road – the B’s could find themselves in big trouble in their quest for a playoff spot. They are already outside the Eastern Conference bracket and all the teams ahead of them, except for the Rangers and Red Wings, have played fewer games than them.

Perhaps that can work in their favor. After the loss to the Habs, David Pastrnak said he felt the team was mentally fatigued and, though that may sound like excuse making to some, the schedule has indeed been brutal.

But make no mistake, there are more issues facing this team than just weariness. While the B’s ability to score goals has been a pleasant surprise, they are not the defensive team they hoped they would be. After back-to-back games in which they gave up 12 goals to Ottawa and Montreal, the B’s are now allowing an average of 3.29 goals a game, ranking them 24th in the 32-team league. Their penalty kill, so solid early in the season, has cratered to 19th in the league at 79.2%. They have now surrendered at least one power-play goal in eight straight games.

While the defensive issues cannot all be placed at the feet of the defensemen – Pastrnak, the team’s leading point-producer with 40, is minus-11 – you do have to wonder what the D corps will look like when this road trip is over. They’ve got four defensemen who are rehabbing from injury. The closest one to returning appears to be Jonathan Aspirot, who coach Marco Sturm said will not be available for the Sabres game but could be after that.

With the way Aspirot played before suffering an upper body injury in Winnipeg on Dec. 11, he deserves to be back in the lineup when healthy. Considering Andrew Peeke’s recent struggles in a top-four role (minus-5 in the last three games, team-worst minus-12 on the season), putting Aspirot with Hampus Lindholm (minus-8) and slotting Peeke on the third pair seems to be worth a try. The left-shot Aspirot showed in ability to play on the right side when Charlie McAvoy was out and essentially played a top-pair role with Nikita Zadorov.

Aspirot is not the only D-man who is nearing a return. Veterans Jordan Harris, Henri Jokiharju and Michael Callahan, a call-up from Providence, are in the mix. Also at their disposal is waiver wire pick-up Vladislav Kolyachonok and Victor Soderstrom, who was returned to Providence just prior to the Montreal game but had played pretty well in his time in Boston.

The old hockey adage says that you can never have too many defensemen, but those are a lot of bodies. It’s hard not to think that B’s management is at least contemplating some sort of move, especially with the most recent struggles. So let’s do a little spitballing.

Mason Lohrei has been an improved player since he was a healthy scratch for five games early in the season, but he’s not the kind of defenseman to be on the ice in key, lead-preserving situations late in a game.

What he could do, at least to these eyes, is run a first power-play unit, but it doesn’t look like that’s in the cards for him any time soon with McAvoy up top on PP1 and the team having success on the man advantage. So if the B’s are not in position to maximize his talents, it would make sense for the B’s to see if they could find a more impactful player for him, whether it’s a decent two-way forward or even if it’s a less flashy but more defensively reliable third pairing.

Will that happen? It’s anyone’s guess. But if they want to keep competing for a playoff spot in these early stages of their rebuild-on-the-fly, they have to figure out a way to better keep the puck out of their own net.