It's the second back surgery in less than a year for the 29-year-old center, who previously had season-ending surgery on Feb. 11.
"They went into the same area and had to do some more repairs," Flyers general manager Chuck Fletcher said. "With Sean, it's been a long road, even going back to June and July. ... He felt tightness, he felt some nerve irritation from time to time. He was told to continue to train, and he felt better as the summer went along, and then prior to [training] camp symptoms seemed to get a little bit worse, so we pulled him back, and at that point we tried to treat it nonsurgically. He got an epidural that brought him some relief for a couple of weeks. He felt great, really the best he had felt in a long time, and then that seemed to wear off and the symptoms came back again.
"So it's sort of been four or five months of this persistent nerve irritation and symptoms. After speaking with a few different specialists, it was decided to go back in and to repair it."
Couturier said he had been cleared in early September for full participation at training camp, which began on Sept. 21, though he never took part in any practices. He had been skating on his own periodically, but coach John Tortorella said Thursday that Couturier had sustained a setback.
"He stopped skating," Tortorella said. "He's just not ready to skate right now. That's a ways away."
Fletcher said there is belief that Couturier can play again this season.
"I think there's finally a little bit more clarity, and hopefully for Sean there's some relief so he can feel better, and then ultimately we're still hopeful he'll come back and play," Fletcher said.
Couturier, who has not played a game since Dec. 18, 2021, is in the first season of an eight-year, $62 million contract ($7.75 million average annual value) he signed Aug. 26, 2021.
Selected by the Flyers in the first round (No. 8) of the 2011 NHL Draft, Couturier has 460 points (180 goals, 280 assists) in 721 games and won the Selke Trophy as the best defensive forward in the NHL in 2019-20. When healthy, he's been the Flyers' No. 1 center, has played on the top power-play unit and is the team's top penalty killer.
Fletcher said he would continue to evaluate for any roster moves but understands the difficulty of replacing what Couturier brings.
"Right now we're still building," Fletcher said. "As John has spoken to a lot, we've integrated a lot of young players and some new players and we have new systems, new coaches. So I think right now we'll probably let things play out, see how we do. It's not easy to replace Sean Couturier, and again the hope is that in 3-4 months he'll be back. So we'll just have to take it game by game and week by week, all the old cliches, but we'll see how it plays out."
Forward James van Riemsdyk is expected to miss six weeks after having surgery to repair a broken left index finger on Friday. He was injured blocking a shot during the first period of Philadelphia's 3-0 loss to the San Jose Sharks on Sunday.
Van Riemsdyk has five points (two goals, three assists) in six games this season.
Fletcher also said there is no update on forward Cam Atkinson, who has not played this season because of an upper-body injury. Atkinson was second on the Flyers with 50 points (23 goals, 27 assists) in 73 games last season.
"He's more week-to-week at this point than day-to-day," Fletcher said. "He's made some progress, and it's been frustrating for him. Nobody wants to play more than Cam. We'll just see how things progress."
