The Devils have struggled of late, especially scoring goals. Devils GM Lou Lamoriello didn't hesitate, swooping in and acquiring the biggest rental player available on this year's trade market.
"It's a bittersweet day but it's behind us and now we have to move forward," Atlanta general manager Don Waddell said of trading the Thrashers' captain.
Oduya has two more years on his deal after this season at a $3.5 million salary-cap hit. Bergfors will be a restricted free agent July 1. Cormier was suspended for the rest of the season in the Quebec Major Junior Hockey League for an elbowing incident but he's a highly regarded prospect.
In addition to Kovalchuk, New Jersey also gets defenseman Anssi Salmela, who was originally a Devil and sent to Atlanta at the trade deadline last year.
The teams also exchanged second-round draft picks in this year's draft.
Lamoriello noted that while the Devils gave up a lot, they have the depth in the organization to overcome it. He also noted that the Devils' recent scoring slump played a part.
"We felt Kovalchuk was a player who could come and fill the need that we felt we had for an explosive scorer and someone who could add a different dimension to our power play with the type of shot," Lamoriello said. "Then it was just the case of trying to make it work somehow where we could not sacrifice tomorrow."
Lamoriello said the Devils have not spoken to Kovalchuk about an extension. He will become a free agent after this season.
Lamoriello said Kovalchuk is expected to play Friday night when the Devils host the Toronto Maple Leafs.
Kovalchuk had 31 goals and 27 assists in 49 games this season for the Thrashers. He missed six games because of a broken bone in his foot.
"The power that he brings; he is a power forward, he has hockey sense and he knows how to make other people around him better," Lamoriello said. "You can tell by the assists he gets. I am sure every one of you has seen him play. What he brings, he can do things a lot of people can't do."
Lamoriello doesn't expect Kovalcuk will have a problem fitting into the Devils' team system.
"The reason we got Alex at that time was for similar reasons: What he could bring offensively with the shot he had and he could do almost individually at times but still be a team player," Lamoriello said. "I feel that Ilya can bring that sort of explosiveness and also I really believe strongly that he wants to win."
The Devils' roster should be bolstered in the next few weeks with the return of forwards Patrik Elias (concussion) and David Clarkson (ankle) from injury. Defenseman Paul Martin is expected to return from a broken left forearm after the Olympic break.
The 28-year-old Oduya has two goals and two assists in 40 games this season. He's set to play for Sweden in Olympics.
Bergfors, a 22-year-old Swede, is fifth among NHL rookies with 27 points (13 goals, 14 assists). He was drafted 23rd overall in 2005.
The 19-year-old Cormier had 11 goals and 20 assists in 31 games this season with Rimouski and Rouyn-Noranda of the QMJHL. He captained Canada in the 2010 World Junior Championship.
"I didn't say we're a better team, but if you watch what's happened, we haven't had great success on the ice," Waddell said of the Thrashers after the trade. "It's not Ilya's fault. It's the team's fault, but we're excited about the future and moving forward."
Salmela, 25, had a goal and four assists in 29 games this season for Atlanta. The Finn was acquired by the Thrashers from the Devils in exchange for defenseman Niclas Havelid and forward Myles Stoesz on March 2, 2009.
Since the Thrashers drafted Kovalchuk No. 1 overall in 2001, the Russian Olympian leads the NHL with 328 goals, but Atlanta, an expansion team that debuted in 1999-2000, has made just one playoff appearance and has never won a postseason game.
"We're struggling with our attendance as it is," Waddell said. "The only way we're going to brings fans back is by winning hockey games."
The Devils lead the Atlantic Division and are in second place in the Eastern Conference standings.
The deal was made hours after Waddell said the franchise would aggressively explore all its options after Kovalchuk rejected a 12-year, $101 million extension.
"We got to a point where we offered the player one deal that was in excess of $100 million," Waddell said. "We haven't won a playoff game here. We have to build this team with that in mind."
Waddell said that if the franchise had met Kovalchuk's salary demands, it would have jeopardized its ability to build a competitive team around him and to retain other young players as they became eligible for new contracts in the seasons ahead.
"I think Kovy right to the last day wanted to be a Thrasher, but again, it becomes a business decision," Waddell said. "In a cap world, you have to make all the pieces fit and if you have one player taking all the room under the cap, it's hard to get all the young pieces to fit as well. ...
"I think it doesn't set us back at all. We picked up some nice pieces today, some nice assets. It's one of those moves you don't look forward to making but we were forced to make it."
Pierre LeBrun covers the NHL for ESPN.com. Information from The Associated Press was used in this report.