BOSTON — Marco Sturm wanted Jonathan Aspirot on his team. He liked the left-shot defenseman’s quick feet and big heart.

But Sturm was the coach of the AHL’s Ontario Reign at the time. Aspirot was playing for the AHL Calgary Wranglers. Sturm didn’t have anything bigger in mind.

So on July 1, 2025, by the time Sturm secured his current gig as the Boston Bruins coach and Aspirot signed a one-year, two-way $775,000 contract with the Bruins, a 2025-26 NHL collaboration was not at the top of mind.

Did he think Aspirot would be an NHLer at the time?

“Not really. Not really. I’m trying to be honest here,” Sturm said. “I knew him. I just didn’t know he had that consistency.”

Sturm had reason for his skepticism. At the time he signed, Aspirot had played 292 professional games over six seasons. All of them were in the AHL. At best, the 26-year-old was No. 9 on the Bruins’ depth chart on defense.

More than seven months later, Aspirot is on the No. 1 duo. Top-pair partner Charlie McAvoy is returning to Boston with gold. The Bruins are the No. 2 wild-card team in the East.

All of this has stretched Aspirot’s imagination.

“Not at all. No,” said the undrafted defenseman when asked if this was how he expected the season to progress. “If you told me about everything that happened last summer, I wouldn’t believe you.”

Aspirot is one of 174 NHL defensemen with 550 or more five-on-five minutes this season, per Natural Stat Trick. Only one among this cohort has a higher goals-for share at five-on-five than Aspirot’s 69.39: Sam Malinski (69.44), whose Colorado Avalanche lead the league in both five-on-five goals scored and allowed. Malinski, 27, was rewarded for his play with a four-year, $4.75 million extension in January.

In terms of bang for the buck, Aspirot and his minimum-wage salary are providing results that his employer could have never imagined.

“His strengths,” Sturm said, “fit our system.”

In Sturm’s hybrid scheme, defensemen have the green light to close on their men high in the defensive zone. Aspirot’s acceleration and go-go willingness put him in an opponent’s face in a hurry. In previous systems, where defensemen were encouraged to hang back and protect the house, Aspirot might not have found as much traction.

Aspirot and McAvoy have shared 190:45 of five-on-five time. The Bruins have outscored opponents 14-9 in those minutes. Both defenders are good at closing. This did not change during their most recent separation.

“Really solid defensively,” Aspirot said of his partner’s Olympic play. “Even saved that one goal at the end there. That was unreal. You could tell it was him. Just super happy for him. He played really solid and stuck to his game.”

Aspirot had a good laugh when told that playing with him got McAvoy ready to run with Quinn Hughes on Team USA’s No. 1 pair. Aspirot noted he does not cover nearly as much ice as Hughes.

But Aspirot, who was not even the Bruins’ first left-shot callup (Michael Callahan was first up following October injuries to Hampus Lindholm and Jordan Harris), has plugged multiple holes during his 36-game run. He started with stay-at-home shifts with Henri Jokiharju on the third pair. He played his off side next to Nikita Zadorov.

Now, given Aspirot’s work with McAvoy, Sturm can roll Lindholm and Zadorov on different pairs and spread out his three best defensemen. Meanwhile, Aspirot’s rise has pushed Jokiharju and Jordan Harris into the No. 7 and 8 slots.

All of this expands general manager Don Sweeney’s options ahead of the March 6 trade deadline. The surplus of defensemen could hint at blue-line movement.

If, for example, another GM targets Mason Lohrei’s offensive upside, Sweeney could move the 25-year-old. Lohrei has most recently been playing his off side next to Lindholm. Aspirot does not have Lohrei’s offensive skill. But Sturm’s system favors Aspirot’s defensive reliability. Like Lohrei, Aspirot can play the right side.

If, on the other hand, a playoff contender favors Andrew Peeke’s defensive presence, Aspirot’s flexibility could convince Sweeney to deal the right-shot defenseman. Peeke’s contract is expiring. The Bruins’ pursuit of Rasmus Andersson signaled that Peeke may not be part of their long-term plan.

As unexpected as it might be, Aspirot has played himself into untouchable territory. It’s not just that he’s producing at an NHL minimum. On Jan. 11, he signed a two-year, $1.775 million extension. A top-pair defenseman who will earn $887,500 annually is not a commodity GMs shed. Even so, Aspirot is not taking job security for granted.

“I think you can never really be safe,” Aspirot said. “As soon as you start being too comfortable, other guys are always pushing to get your job. It’s just working, especially being in this league. You always try to be better every day and always working hard. You can’t really sit down and say, ‘I’m all set.’ That’s the mentality we have, something we try to do every day, is to get better.”