It’s looking more and more like the Bruins defense corps on Opening Night won’t be much different than the unit that struggled mightily last season, and that’s a bit of a short-term bummer.

But the future looks undeniably bright when you pan back for a long-term view. That much was obvious after watching last week’s Development Camp at Ristuccia Arena and seeing the young talent the Bruins have on the blueline.

Dennis Seidenberg is gone after being bought out of the final two years of his contract, and it’s not out of the realm that captain Zdeno Chara could be moved at the next trade deadline if the B's are once again flailing in the Eastern Conference. As those long-time stalwarts depart, younger vets like Torey Krug (who just signed a five-year extension) and Kevan Miller (benficiary of a head-scratching four-year contract) will be forced to step into leadership roles. Even younger d-men like Joe Morrow and Colin Miller will see their ice time increase. It could be a painful transition season,

But behind them comes hope. Charlie McAvoy, Jakub Zboril, Jeremy Lauzon, Brandon Carlo and Matt Grzelcyk all skated, moved the puck, and competed like future NHL players at last week's camp.

“[Defense has] been an area of need that we wanted to address," said general manager Don Sweeney. "It’s something I identified in taking over, that we hadn’t drafted a lot of players in the first two rounds of previous drafts on the back end. So it was an area we targeted . . .

“These [defensemen] are all going to grow up together, and be a big part of our future going forward. You add [those younger guys] to Matt Grzelcyk and Robbie [O’Gara] coming out of college that are a little older. It’s a good group.

"Patience is a word that’s not readily thrown around in this marketplace, and I understand that. We’re in a competitive business, and we want to win every year. But you have to grow your players, I firmly believe that and I’ve been committed to that since I took over the job. Working in development, I have always believed that the internal search is the best place to find your players. I think we’re in a much stronger player to allow these players [to succeed], and they have to hit. If they don’t [hit] then that’s on us for misidentifying them.”

That's why Sweeney may stand pat with his NHL roster heading into camp, and will only look to upgrade with a defenseman like Kevin Shattenkirk or Cam Fowler if the price is right. The Bruins have more than $6 million in cap space to make a significant upgrade, but by the sound of it there would have to be corresponding salary-cap moves as well.

“It’s only July," said Sweeney. "Do I think there are opportunities to continue to explore and improve the roster? Sure. But part of that was the draft, where everybody was trying to do that as well, and you have to balance the prices of acquisition and see whether or not you find a fit. Teams are thinking the same thing: They’re kind of looking at their roster and seeing how it all takes shape. They might be more inclined (to make moves) whether it’s August or September, or whatever the case may be. We’re in a position now to act upon that, and we have some [cap] flexibility. We’ve been planning for this year, next year and the years after that. We (want to) maintain that flexibility while building the best possible team we can.

"I think we’re an improved hockey club. We addressed some areas where we wanted to get deeper: Certainly the middle of the ice, penalty-killing and a little more balance on the back end to have transitional play getting back on pucks, moving pucks. We have players that need to continue to gain experience, but where are they going to do that except at the National Hockey League level? Are they ready to assume large roles? That’s to be determined. It’s not going to stop me from thinking about tinkering, or acquiring, a player with a more ready-made (ability to contribute). But there are two sides to that. We feel comfortable (with our roster), but we want to continue to improve.”

The one caveat to all this: There’s a very realistic possibility that if (when?) Jimmy Vesey signs with the Bruins on Aug. 15, a forward currently on the roster could be used in a trade for a puck-moving defenseman.

But the Bruins also clearly feel that the 6-foot-5, 203-pound Carlo -- only 19 years old -- could be ready to contribute as soon as this season, and could make a player like Adam McQuaid expendable in trade. He looked massive, strong and a little surly in the D-zone during drills, and has surprised to this point with enough offensive instincts to project as a top-4 guy . . . provided he’s paired with a puck-mover like Krug.

Beyond that, McAvoy looks like a durable, skilled and smooth puck-moving defenseman who could be the top-pairing D-man the Bruins have been looking for, and that would be a welcomed addition a couple of years down the line. McAvoy, 18, aspires to be Drew Doughty. He certainly plays well at both ends of the ice -- like someone of Doughty's caliber -- and the B’s are hoping he turns into some facsimile of the No. 1 franchise D-man.

“He was as advertised for me,” said Sweeney. “Obviously it’s not a physical environment. There’s competitiveness and battling for pucks and space, but (at Development Camp) we’re not looking for guys to step up in the neutral zone. Charlie has shown the ability to step up and do that even as a freshman at the college level and you realize he moves around so well.

“The two-way component to his game and the upside to play both sides of the puck, those are the guys that log a lot of minutes at the NHL. I think he tracks the same in that regard.”

Zboril was a disappointment in junior hockey last season after being Boston’s top pick in the first round last summer. But he looked strong, fast and competitive at camp, along with being in much better shape as he took the whole experience a little more seriously.

If there was any "bust" talk with the 19-year-old Zboril (which would be ridiculous to begin with, given the age of the player), it's gone now after watching a week of tape-to-tape passes and players bouncing off him in one-on-one battles all over the ice. It was an encouraging week, and his stock is once again rising in the organization.

“He was much more prepared this year, and you expect that,” said Sweeney. “He had a year that was up-and-down a little bit, particularly offensively in a bit more of a shutdown role. He’s in much better shape, and you see his skill-set that he certainly self-selects in that regard. We’ll continue to push in the areas he needs work at, but he’s got a fundamental base that is awfully good.”

Lauzon wasn’t as flashy in a lot of the drills on the ice, but the Bruins coaching staff raves about his competitiveness in run-of-the-mill drills and the way his quality of play rises once the puck is dropped in game situations. He's another player who could end up playing in all situations, and could really flash in training camp this fall if the NHL speed and physicality isn’t too much for him.

“His compete level is off the charts,” said Sweeney of Lauzon. “Developmentally, he’s got areas to focus on just like everybody else. We’ve identified them and we’re going to continue to talk about, but he’s excited to come to camp. The players themselves determine when they play, and their trajectory is not pre-determined. It’s a matter of getting into situations, and then proving you can handle it and then moving forward.”

Grzelcyk is the oldest, at 22, and the most experienced after playing four seasons for Boston University, but he also might be most in need of AHL seasoning given his size and specialized game on the ice. Grzelcyk will need to learn how to survive in the pro game at 5-foot-10 and 176 pounds, and will undoubtedly be organizationally blocked by the similarly lefty-shooting Krug for the foreseeable future. To put it another way, Grzelcyk may assume the David Warsofsky role: AHL workhorse who will be called upon should (when?) the 5-foot-9, 181-pound Krug get banged up during the season. Krug is a tough and durable customer, but he’s also coming off major shoulder surgery after his first season handling a top-4 D-man workload.

The aforementioned names don’t even include 6-foot-4, 207-pound Yale product Robbie O’Gara, who is also joining the Bruins for his first pro season after a summer working out at the summer pro league at the Foxboro Sports Center.

That’s a lot of young, talented defense prospects who could be NHL-ready within the next two years, and who could switch the back end from weakness to strength if the proper patience is observed in Boston. The one key: One of those six names needs to develop into a Duncan Keith- or Kris Letang-type No. 1 defenseman, capable of playing heavy playoff minutes, maintaining a high level of play throughout the massive workload, and still holding that electric ability to dominate play even at the highest levels of play.

That’s a tall order. But it’s what must happen for the Bruins to once again seriously compete for the Stanley Cup.

The roster as currently constituted, with the same D-corps as last season, will be lucky to back into the playoffs, and that's if everything goes right. But last week showed that the future looks bright.