The New York Rangers, the New York Islanders and the New Jersey Devils begin their NHL seasons this week eager to see how offseason transitions will manifest on the ice.

The Devils entered the offseason with Lou Lamoriello having completed his 27th year leading the front office. In May, soon after the regular season, Lamoriello announced the hiring of the veteran executive Ray Shero as the team’s general manager while Lamoriello remained president. That arrangement lasted two months, though, as Lamoriello departed for the Toronto Maple Leafs.

That left Shero in charge.

Shero, who was the Pittsburgh Penguins’ general manager for eight seasons before being fired after the 2013-14 season, said he was rejuvenated after spending a year out of an NHL front office. His plan to rebuild was evident from the start, as the Devils have striven to get younger this season. They were the oldest team in the league last season and averaged only 2.2 goals per game during a 78-point campaign, their worst since 1989-90. They missed the playoffs for the third straight season since reaching the Stanley Cup finals in 2012.

“I think some of the things we did not do this summer, some of the players we did not re-sign, is pretty clear of the vision we have,” Shero said. “There will be a time and a place to take a step, and our ownership supports that. To me, it’s about building up the assets in the organization, working with these younger players. We have some good things in place, and we have to be a lot better.”

The Devils added 24-year-old center Kyle Palmieri, who grew up in New Jersey. They signed defenseman Adam Larsson, 22, to a long-term deal, and will have six defensemen 25 or younger when they open the season Friday at home against the Winnipeg Jets. The Devils also have high hopes for the first-round pick Pavel Zacha, an 18-year-old center.

Part of getting younger was hiring coach John Hynes, 40, who spent the last six seasons leading the Wilkes-Barre/Scranton Penguins of the American Hockey League.

He is the youngest coach in the NHL, culminating nearly two decades of coaching at most every level of hockey in the United States. He was a college assistant before leading the national development program for junior hockey for six seasons. He cites communication and a need to manage players the same way an executive would as his best assets for the job.

“Three important things to me that categorize a really good coach: the ability to teach, the ability to inspire people and discipline people,” Shero said. “I think he’s got them.”

In recent years, the Rangers have been the area’s most stable team and the most consistently successful, but they experienced a changing of the guard of their own in the front office, where rising star executive Jeff Gorton has taken over from Hall of Famer Glen Sather.

The Rangers, who open in Chicago, had many teams asking for permission to interview Gorton for general manager vacancies, including the Boston Bruins and the Toronto Maple Leafs.

Sather, who turned 72 last month, remains team president and has been visible at Rangers practices during training camp. But after 35 years as a general manager — first with the Edmonton Oilers before spending the last 15 with the Rangers — he is happy to take a step back.

“It’s been a long time,” Sather said on a conference call in July. “I’ve pretty much spent my life doing this: playing, coaching and managing. I just felt it was time to move a little bit.”

Gorton, who is in his ninth year in the Rangers’ front office, has already drawn praise for his handling of Derek Stepan’s new contract, and he has surrounded himself with a brain trust that includes Sather, former NHL coach Jim Schoenfeld and former Rangers forward Chris Drury.

The core of the team that took the Rangers to Game 7 of the Eastern Conference finals a year ago is intact. The Rangers reached the Stanley Cup finals two years ago and are again among the favorites in the East.

Still, as the team makes decisions on this season’s roster, Gorton’s mettle will be tested. The Rangers’ salary-cap situation forced them to trade Carl Hagelin in the offseason, and the top player they received in return — Emerson Etem — has had an unimpressive training camp.

It took Sather four seasons to field a playoff-caliber roster in New York, and with a roster in win-now mode, Gorton will be forced to juggle prospect development with building a championship-level roster.

“He has earned the respect of colleagues throughout the hockey community,” Sather said. “He is well prepared for and extremely deserving of this opportunity.”

With the sudden changes in the front offices of the Devils and the Rangers, the Islanders’ Garth Snow, with more than nine years in the job, is the longest-tenured general manager in town and in the Metropolitan Division.

Snow added former Washington Capitals general manager George McPhee to his front office as an adviser, and after a 101-point season, there are high expectations for the Islanders to win their first playoff series in 22 years.

The Islanders are not without an alteration to last year’s routine, as they migrated about 30 miles west to occupy Barclays Center in Brooklyn, where they host the Blackhawks on Friday.

The Islanders will reap a handsome reward for this move, with Barclays Center paying the club millions annually to play there.

Snow has locked up several important players, including defensemen Johnny Boychuk and Nick Leddy and forward Brock Nelson, with long-term contracts.

Still, many fans have bemoaned the move, criticizing the goal horn, the team’s new third jersey and the many obstructed-view seats.

Barclays Center is far superior to the Coliseum on paper, but it is still figuring out how to function for two tenants. As the Islanders await renovations on their new East Meadow practice complex, they will practice in Syosset, more than an hour away from Barclays Center via the Long Island Rail Road.

Many of the players will continue to reside on Long Island, creating a routine akin to road games, where they will stay in a Brooklyn hotel the night before games, participate in morning skates and games in Brooklyn, then return home after them.

They have practiced this throughout the preseason, and it is becoming more familiar.

“We don’t have much choice,” defenseman Travis Hamonic said. “We’re going to have to get used to it.”