The news, first reported by Sports.ru's Igor Eronko, caught the Flyers by surprise.
"I spoke with Erik and he informed me that he does, in fact, have a deal in place to play overseas," general manager Ron Hextall said. "Although we are disappointed in his decision, we wish him all the best."
Gustafsson, 25, will leave the Flyers short of a young, inexpensive blueliner. He was set to become a restricted free agent again this summer. He earned $1 million last year in his first full season in the NHL, but appeared in only 31 games - one above his career-high mark set in a year he shuttled between the AHL and NHL.
In Omsk, he likely will earn more money and a guaranteed top-six role. He is currently skating on Sweden's top defensive pair in the World Championships.
According to a team report, the Flyers will extend a qualifying offer to Gustafsson this summer for $1,050,000, which will retain his rights for next season should he decide to return to the NHL. He could rejoin the team before Dec. 1 to be eligible for the season.
The Flyers had interest in keeping Gustafsson on the roster for next season, even though it was unlikely he would crack the top three pairings, which are mostly already set. His sudden departure does decrease the flexibility Hextall had to move one of those top six defensemen without a return in the same position.
One bright spot is the Flyers now have room for a prospect on their roster, including either Shayne Gostisbehere or Robert Hagg. Hextall made it clear in his initial news conference that he will not rush prospects to the NHL, but the Flyers have a need for substantial contributors who are small chips on their salary cap next season.
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