Couturier last played Dec. 18. He scored 17 points (six goals, 11 assists) in 29 games.
He is expected to need three months to recover and to be ready for the start of next season.
"This wasn't an issue that was bothering him coming into the year," Flyers general manager Chuck Fletcher said Friday. "He started having issues in the fall and tried to battle through. We tried to treat things nonsurgically, couple epidurals to be exact, to try to resolve the issue that was there. You try to do your best to avoid back surgery if you can, but ultimately the doctor and Sean felt confident that the best way to resolve this going forward was to have this surgical intervention."
The Flyers are 3-12-3 without Couturier after they were defeated 4-2 by the Detroit Red Wings on Saturday. Couturier was expected to be their No. 1 center this season.
The 29-year-old signed an eight-year, $62 million contract extension Aug. 26. The contract, which begins next season, has an average annual value of $7.75 million.
The Flyers expected to have Couturier, Kevin Hayes, Derick Brassard and Patrick Brown as their top four centers, but they were in the lineup at the same time in two games, Nov. 13 and Nov. 16.
Hayes has been limited to 20 games because of three surgeries to his midsection since the end of last season, including a procedure Jan. 18 to drain fluid from the adductor region of his hip.
He was expected to need 3-4 weeks to recover and is skating, but Fletcher said it was, "50-50 he can come back and play," and could need another surgery to his midsection, which would end his season. He previously had core muscle surgery in May and abdominal surgery Sept. 21 that caused him to miss the first 12 games of the season.
"It's been certainly a lot going on in that area for him, the core muscle, the groins, everything," Fletcher said. "We're doing what he can. He's seeing different specialists. I feel we have a good grasp on where we're at. We're going to have to see how he responds to the treatment and the skating he's doing now."
Brassard has been limited to 20 games because of a lower-body injury sustained Nov. 23; he has played three games since then, including a 6-3 loss to the Detroit Red Wings on Thursday which was his first game since Jan. 6. Brassard did not play Saturday.
Brown has missed 12 games with a sprained MCL in his knee and missed seven with a thumb injury sustained Nov. 16.
Defenseman Ryan Ellis, out since Nov. 13 because of a lower-body injury, also could need season-ending surgery.
The Flyers acquired Ellis in a trade with the Nashville Predators for forward Nolan Patrick and defenseman Philippe Myers on July 17 and expected to play him on the right side of their top defense pair with Ivan Provorov.
Ellis has played four games this season, none since Nov. 13, because of a lower-body injury that dates to training camp.
"We've been trying to avoid surgery and look at different ways of rehabbing and treatment to allow him to play," Fletcher said. "We're starting to get to a point in the year though where obviously his health is first and foremost and the second issue is making sure he's ready for next year. We're getting close to that point."
Ellis scored five points (one goal, four assists) in four games.
The Flyers also are without forwards Nate Thompson (shoulder), Joel Farabee (upper body), and Wade Allison (knee).
