With the Boston Bruins set to open the 2015-16 regular season this Thursday, NESN.com is bringing you a position-by-position preview of this season’s squad. Next up: the blue line.

The Bruins’ defenseman corps this season is an intriguing blend of old and new.

Three of its members were part of the 2011 Stanley Cup team, including Dennis Seidenberg, who will miss at least six more weeks after undergoing back surgery.

Three others played more games in the American Hockey League last season than they did in the NHL, and one of those, former Los Angeles Kings prospect Colin Miller, has yet to make his NHL debut.

Rounding out the crew are Matt Irwin, who is in his first year with the Bruins after a trade from the San Jose Sharks; Kevan Miller, who lost half of last season to a shoulder injury; and Torey Krug, a top-notch offensive D-man looking to prove he can excel in a top-four role.

But the Bruins’ most important blueliner also is the one whose status is most in question entering opening night.

Zdeno Chara, 38, logged just three shifts in the preseason after suffering an upper body injury, and as of Wednesday night, the team had not confirmed whether he’d suit up for Thursday’s regular-season opener against the Winnipeg Jets or remain on injured reserve. Given the captain’s recent injury history (he missed 19 games last season), a cautious approach is understandable.

But with defense widely considered Boston’s greatest weakness following the offseason departure of Dougie Hamilton, a healthy Chara will be a near necessity for the Bruins this season.

“I noticed it last year how big of a deal he actually is out there,” goalie Tuukka Rask said Wednesday in an interview with 98.5 The Sports Hub’s “Toucher & Rich.” “He’s such a big presence in front of that net, clearing pucks out, taking guys out and what not. When we lost him (last year), it was a huge blow. And I don’t think people realized how big of an influence he actually is until he was gone. We’re all hoping he gets back soon, because he’s a great part of our defense and team, inside the locker room and also on the ice.”

But even if Chara plays all 82 games, question marks still abound on the B’s blue line.

Are 25-year-old Zach Trotman and 22-year-old Joe Morrow, with a combined 44 NHL games and six points to their credit, ready to be everyday players? Will Colin Miller’s AHL dominance make for a speedy transition to the big club? Can the other Miller stay healthy?

Those questions won’t be answered immediately, and the early portion of this season likely will feature a great deal of growing pains. But for what it’s worth, the young Bruins blueliners already have their goalie’s stamp of approval.

“I feel very confident, and everybody else feels very confident, too,” Rask told “T&R.” “Obviously, there’s some young guys, some unproven guys, but they’re all good players. And it’s just a matter of, if you don’t have that size, you have to bring something else, and I think now we have a lot of skill, a lot of speed, and guys can still battle. Those days are long gone when we had Johnny Boychuks and guys like that who were blocking every shot and battling in front of the net and stuff like. I think these guys coming in are just smart and very skilled players.

“I’m actually excited about this, because I think they’re going to surprise a lot of people with how good they are.”

Thumbnail photo via Greg M. Cooper/USA TODAY Sports Images

Thumbnail photo via Boston Bruins defenseman Zdeno Chara during a game against Florida.