"The structure of the knee is fine. He's got good cartilage on both sides of the knee," Holmgren said.
Pronger had some "loose bodies" removed in his right knee on July 27, 2010, and he didn't get into the lineup until Oct. 11, missing the first two games of the season.
This season, Pronger has missed 10 games, including six after he took a stick to his eye. The Flyers are 5-4-1 without him this year.
In the last two seasons, Pronger has missed 42 regular-season games; the Flyers have won just 21 of them.
Pronger, 37, has been sidelined the last four games with a virus.
"We were hopeful with the time missed with a virus, things would settle down in his knee," Holmgren said.
But that didn't happen.
It appears Pronger will play in the Winter Classic on Jan. 2 against the New York Rangers. But 24/7 - the HBO series that leads up to the game - probably won't feature much of Pronger's biting, sarcastic humor.
Pronger's surgery will be performed by Peter DeLuca.
Holmgren said Pronger has been bothered by a nagging, sore knee for about a month. "He's been playing through it until this recent bout with his virus," the general manager said.
After Pronger had an MRI on Sunday, "we decided it was time to get this taken care of," Holmgren said.
Asked if he was worried that Pronger's age was catching up with Pronger, Holmgren said: "Chris is a player who takes good care of himself, does the proper rehabilitation and conditioning to stay in top shape. I think this time, the only thing we can do is go by what the doctor tells us . . . and it's just a question of cleaning some of those [loose] bodies."
Holmgren said the organization was "worried because he's going under surgery, but long term, I still think Chris has lots of miles left on his body."
Holmgren also announced that forward Brayden Schenn was recalled from Adirondack and that winger Andreas Nodl was placed on waivers. Defenseman Kevin Marshall, who played against the Rangers on Saturday and then was sent to the Phantoms, was also recalled.
If Nodl clears waivers Tuesday, the Flyers will decide whether to keep him on their roster or demote him to the Phantoms.
For the time being, the Flyers' defense will include two rookies, Marshall and Marc-Andre Bourdon. The defense will be anchored by veterans Kimmo Timonen, Braydon Coburn, Matt Carle and Andrej Meszaros.
Pronger and defenseman Andreas Lilja (ankle) will go on the long-term injured list, giving the Flyers about $4.3 million in cap space.
Holmgren may explore the trade market for a proven defenseman. He also might try to sneak the Phantoms' Matt Walker ($1.7 million cap hit) through reentry waivers and back to the Flyers. Another team could claim Walker for half the price, prorated by the number of games remaining.
It is likely the Flyers will add a defenseman before they play in Anaheim, Calif., on Friday; they do not want to be so far away with just six healthy defensemen.
In other matters, winger Jaromir Jagr, rehabbing after a groin injury, skated Monday, and there is a chance he will play Friday. James van Riemsdyk, another injured winger, is a longshot to play this weekend, according to Holmgren.
Contact staff writer Sam Carchidi at email@example.com or on Twitter @BroadStBull.