WILMINGTON, Mass. - The Bruins will have a younger team this season than they did in 2014-15. General Manager Don Sweeney has had his sights set on that since being hired in May.

Chris Kelly is on board.

“That’s hockey. I think that’s for every team, you know, very rarely do you see a team just keep getting older and older and older,” the alternate captain smiled following an informal practice at Ristuccia Arena on Thursday.

“Yeah, you have players that get older, but there’s always new young guys that come in and filter in. That’s the great thing about hockey; regardless of age, you always feel like you’re 24.”

“You know, if you’re [19] like David [Pastrnak], you’d think he was 24 because he’s way more mature than I think most [19] year-olds. But if you’re older,” he paused, jokingly lifting his head to glance at 38-year-old Captain Zdeno Chara’s locker room stall, before deciding to mention someone his own age. “Like Seids [Dennis Seidenberg], you know, you’d think Seids is 24.”

“So I think age is such a mindset, a label that is put on players,” said the 34-year-old Kelly. “But I feel good with the young and the old guys that are mixing and gelling.”

The crop of young players includes Pastrnak, 23-year-old forwards Ryan Spooner and Brett Connolly, and 25-year-old defenseman Zach Trotman, all of whom finished the 2014-15 season with Boston.

Pastrnak is bound for a breakout season after putting up 27 points as a rookie (and looking to disprove the “sophomore slump” onus often put on second year players), while Spooner looks to make a greater impact at the NHL level, having posted 18 points in 2014-15. Trotman, on a one-way deal for the upcoming season (that will pay him an NHL salary whether he’s in the NHL or AHL ), will try to prove he’s a reliable member of Boston’s top-six on defense.

Even without Dougie Hamilton, the Bruins will remain young on the back end with Trotman and 24-year-old Torey Krug. Newcomer Colin Miller and Joe Morrow, both 22 years old, will compete for spots on Boston’s blueline out of training camp.

Among the Bruins’ new acquisitions are 25-year-old forwards Jimmy Hayes and Zac Rinaldo. Young forwards pushing for spots include Brian Ferlin (23), Seth Griffith (22) and Alexander Khokhlachev (21).

Boston’s leadership core remains, with the likes of Kelly, Zdeno Chara, Patrice Bergeron, David Krejci, Tuukka Rask and Brad Marchand. Longtime Bruins Milan Lucic, Gregory Campbell and Daniel Paille will not be back.

“You know, I think we still have a strong group,” Kelly said. “I know we lost some guys, but you know, [we’re] a strong mature group that’s been through a lot, that knows how to handle different situations on and off the ice.”

“And when you look around the room, the guys that maybe haven’t been seen as leaders have grown into those and that’s spread out throughout the room; you can tell.”

With a mix of veterans and newcomers, and a fresh boost of youth, Kelly - as a leader - is excited to see how the team will form and build chemistry.

“I think there’s some sadness to see some guys go and some teammates and friends that you’ve become quite close with, [but I’m] also excited to see new guys coming in and meet them,” he said. “It’s obviously a fresh start for some guys.”

Hayes, Rinaldo and Matt Beleskey are all new faces at the informal practices being held at Ristuccia Arena in advance of training camp, which begins in mid-September.

When thinking about camp and how the roster is going to play out, it is too early for even Kelly to be thinking about what the line combinations will be.

“I thought I’d leave that up to you guys,” he smirked. “No, to be honest. You know, you just come in and you play; they put you where they feel is best for the team and then you go from there.”

“You learn about things you can control and things you can’t control and things to worry about, things not to worry about. You just come in and try to be in the best shape possible and work hard in the offseason and come into camp and have a good team.”

With all of the changes in the offseason, questions surrounding the team during free agency and trade rumors, Kelly is just glad that he’s still part of this group heading into camp.

“I’m happy to be back, obviously,” he said. “Boston’s a great place, we’ve got a great team and I think we’re excited to start up and hit that point where you just want camp to start and you want some games to come and then the season to start. I think we’re all anxious to get rolling again.”