BOSTON — Mark Kastelic is the Boston Bruins’ best faceoff man, winning 58.3 percent of his draws. This has turned Kastelic into a singular type of faceoff specialist: drop man to start overtime.

Kastelic, the No. 3 right wing, is tied for 11th in team scoring (4-4—8). Coaches do not usually deploy such forwards during three-on-three overtime. They ride their best offensive players, the ones with the quickest feet and softest hands.

But for the Bruins’ last three overtime games, Marco Sturm has told Kastelic to take the opening faceoff. If he gains possession, he changes for a more offensive teammate. He has won two of his last three, including on Saturday against the Detroit Red Wings’ Dylan Larkin.

Kastelic takes this job seriously.

“I feel like I have a role and little moments like that where I feel like I take a lot of pride in personally,” Kastelic said after the 3-2 shootout win over the Red Wings. “It’s great to feel the trust from the coaching staff to get put in those big moments. It’s been pretty cool to go out there. Guys on the team, it’s such a little thing, but they hype me up so much.”

Kastelic averaged 10:44 of ice time per game last season. He played a total of 15:01 on the penalty kill in 61 games for ex-coaches Jim Montgomery and Joe Sacco.

This year, he’s up to 13:43 per game. He is averaging 2:20 on the PK per appearance. Both are career highs. The straight-line forward has earned Sturm’s trust, and not just for dropping Moritz Seider in the first period.

“He’s already waiting for it,” a smiling Sturm said of Kastelic’s OT assignment. “That’s the best part. Talked to him about it, and he’s like, ‘Yeah, that’s my job. I want to do that.’ As soon as it’s OT, I can see him looking.”

It may seem like a coach’s minor decision. But it has major implications for Kastelic. It gives him an extra layer of belonging.

The blue-collar Kastelic needs no urging to execute team-first actions, whether it’s standing up for a teammate or blocking a shot. But when a coach shows his faith, a grinder like Kastelic will do whatever it takes to help the team win, especially when it’s short-staffed.

“When we play our system, it doesn’t really matter who we have in the lineup,” said Kastelic of a roster currently missing Viktor Arvidsson, Matej Blumel, Jordan Harris, Henri Jokiharju, Charlie McAvoy and David Pastrnak. “Everybody can play that way. I don’t think it’s very fun to play against for the other team. When we play with a lot of structure, it really limits their chances.”

The Bruins are in second place in the Atlantic Division. The airtight goaltending of Jeremy Swayman has a lot to do with that.

But it is also about the merging of Sturm’s defense-first philosophy and general manager Don Sweeney’s roster-building. The two have come together ahead of schedule.

“They’ve taken on his identity as a person and as a coach,” said Detroit coach Todd McLellan, Sturm’s former boss with the Los Angeles Kings. “You can see they’ve bought in to his belief system. There’s nothing tricked-out about their game other than that they play hard for a full 60 minutes. So if you’re not prepared to meet that match, eventually they’ll get the best of you at some segment of the game.”

All the proof Sturm needed for the Bruins’ accelerated turnaround from fifth-worst team to playoff contender was the booing he heard at TD Garden during Friday’s 6-2 loss to the New York Rangers, It was the first home game following a four-stop road trip, including three in California. These are difficult ones to play, doubly so for a lineup missing star players. Fans would not have booed if they didn’t expect more.

“I’m very pleased with the first 30 games in our season,” Sturm said. “The way we went, sometimes I think we spoiled everyone too much a little bit because we went too fast. Games like the other night, that’s going to happen too. At the end of the day, I know who we are. We want to be consistent.”

Kastelic, acquired from the Ottawa Senators in the Linus Ullmark trade, has grown into a legitimate third-liner. So has Tanner Jeannot, who is up to 13:44 of average ice time per game from 11:01 last year with the Kings. Jeannot is fulfilling his five-year, $17 million contract. They are Sturm’s primary musclemen, tasked to be bears on the forecheck and animals with their gloves on the ice.

As for Sweeney’s other recent transactions, Mikey Eyssimont, Sean Kuraly, Alex Steeves and Jeffrey Viel are playing to expectation. Jonathan Aspirot, who had never played an NHL game before this season, is playing like a veteran. Fraser Minten is growing by the game. Marat Khusnutdinov and Nikita Zadorov have taken big steps.

In terms of grand slams, it is difficult to find a signing sharper than the six-year, $33 million extension Sweeney gave to Morgan Geekie. The red-hot winger is keeping pace with Nathan MacKinnon atop the goal-scoring race at less than half the annual price. Geekie has shed every perception, from being a shooting percentage outlier to a Pastrnak wingman. With Pastrnak and McAvoy missing, you could make the case Geekie is the lone high-end model in the team garage.

“Sometimes it doesn’t look too sexy, the way we play, because we have a lot of guys out,” Sturm said. “We don’t have too many high-end scorers. Geeks, sometimes he takes it personally. He wants to be the guy.”

The Bruins have blemishes. They are 10th in the Eastern Conference in points percentage (.556) and 11th in goal differential (minus-3).

But they are in the fight — earlier than expected.