The 30-year-old Kovalchuk walked away from the $77 million that was left on the 15-year contract he signed with New Jersey in 2010, including guaranteed annual salaries of at least $11 million over the next four seasons.
The Devils announced the news Thursday afternoon, saying that Kovalchuk alerted Lou Lamoriello, the team's president and general manager, earlier this year that he wanted to return home to Russia with his family after 11 seasons in the NHL.
"This wasn't a decision made by the New Jersey Devils," a testy Lamoriello said at the end of a conference call with reporters less than an hour after the retirement was announced.
Lamoriello refused to disclose anything about his conversations with Kovalchuk relating to the surprising retirement.
He also didn't clarify whether Kovalchuk planned to play in Russia's KHL next season—as is expected—or whether the Devils would retain his rights if he reconsidered his retirement, deferring to the NHL.
"All I know is that he will not be playing here at his desire," said Lamoriello, who built the Devils' three Stanley Cup championship teams and had hoped Kovalchuk would be the centerpiece of a fourth.
Lamoriello said Kovalchuk's retirement wasn't related to anything physical. The forward had back problems during the 2011-12 season and missed 11 games this year because of a shoulder injury.
"This decision was something I have thought about for a long time going back to the lockout and spending the year in Russia," Kovalchuk, the No. 1 overall pick in the 2001 draft, said in a statement. "Though I decided to return this past season, Lou was aware of my desire to go back home and have my family there with me. The most difficult thing for me is to leave the New Jersey Devils."
Kovalchuk was to earn $11.3 million in each of the next two seasons and $56 million over the next five years. Lamoriello said Kovalchuk didn't receive a signing bonus, so the team isn't seeking to recover any money from him.
"I am never surprised about anything that happens in this game today," Lamoriello said.
The defection means the Devils have lost a top player after each of the past two seasons. Zach Parise signed as a free agent with Minnesota after New Jersey's run to the 2012 Stanley Cup finals.
Kovalchuk's exit now deprives the Devils of a star outside of aging goalie Martin Brodeur, who is far from his prime now that he is 41.
Lamoriello wouldn't say whether the team would've done anything different had the Devils known of Kovalchuk's decision before the NHL free-agent signing period began last week.
New Jersey lost forward David Clarkson, who signed with Toronto after posting 30 goals during the 2011-12 season and 15 while playing in all 48 games during this lockout-shortened campaign.
The Devils did re-sign forward Patrik Elias and added some punch to the lineup by reaching deals last week with free agents Ryane Clowe and Michael Ryder.
"We're going to put the best possible team we can on the ice," said Lamoriello, who insisted his main focus is on moving forward.
Lamoriello wouldn't say whether the retirement soured him on Kovalchuk's four seasons with the club, but he gave the clear impression that he was miffed.
The Devils gave up a lot to get Kovalchuk from Atlanta in 2010 and maybe even more to keep him after he became a free agent following that season.
New Jersey sent defenseman Johnny Oduya, then rookie forward Niclas Bergfors and junior prospect Patrice Cormier, and a first-round selection in the 2010 draft to the Thrashers for Kovalchuk and defenseman Anssi Salmela.
After the season, the Devils signed Kovalchuk to a 17-year, $102 million contract that the NHL ruled circumvented the salary cap. The league subsequently fined New Jersey $3 million and took away two draft choices: a third round pick in 2011 and next year's first-round pick.
In tying up a huge chunk of money in Kovalchuk, the Devils also didn't have as much to offer Parise and possibly Clarkson the past two years to try to keep them with New Jersey.
Kovalchuk spent his last four seasons with the Devils. His best was the 2011-12 campaign in which he scored 37 goals. He had 11 goals in 37 games this season.
Kovalchuk scored 417 goals and 399 assists in 816 career NHL games. His best seasons were 2005-06 and 2007-08 when he scored a career-high 52 goals. He had three other 40-goal seasons.
He represented Russia at three Olympic Games, nine World Championships, one World Junior Championship and the 2004 World Cup.
Kovalchuk played in the KHL with SKA St. Petersburg during the recent lockout and was selected as team captain. He could be rejoining that club soon.
He participated in the KHL All-Star game before returning to New Jersey after the lockout. The Devils, however, failed to qualify for the playoffs in the season after they were Eastern Conference champions.