The Flyers had projected he would return to the lineup in late December.
Now, there are questions. Lots of questions.
"Over the last few days, he's had some difficulties - a fairly persistent headache, just a sluggish feeling. . . . So we're just trying to do the right thing here and get him checked out by the doctors in Pittsburgh and see what we're dealing with," Holmgren said after the Flyers held an optional skate in Voorhees. "Is it a concussion? I don't know that we know that just yet. We want to get a better idea, obviously."
Pronger declined an interview request, saying he would talk after his appointment Wednesday.
Asked if Pronger actually had a virus, as the team first thought, Holmgren said: "That's a good question. I don't know that we'll ever know that. We didn't know what we were dealing with then, and I'm not sure we know now. Concussion-like symptoms continue to persist, and we're just going to get him checked."
The Flyers have won four straight and are 9-4-1 without Pronger this season; they are 8-3-2 with him.
"When he gets himself healthy and gets himself back, it'll be a great addition to our lineup," defenseman Braydon Coburn said, "but we have guys that have to step up in his place."
For the time being, Holmgren does not see a need to make a trade for a defenseman.
"We have seven defensemen right now that are healthy, and we're happy with their play," Holmgren said. He said he talks with general managers "every other day" about players who are available, "but I like the way our team's playing right now. I like the way the young kids have played on defense, and I don't feel the need to really rush into anything."
The Flyers are 6-2 in their last eight games without Pronger, and they entered Friday atop the Eastern Conference. Holmgren praised the work of veterans Kimmo Timonen, Matt Carle, Coburn, and Andrej Meszaros for keeping the defense running smoothly. He also has been happy with rookie defensemen Marc-Andre Bourdon and Kevin Marshall.
Pronger's medical woes this season started when he was inadvertently hit by a stick against Toronto on Oct. 24. He missed six games and returned to the lineup and played five games before being sidelined by what the Flyers called a virus. At the time, Holmgren said the virus was not connected to the eye injury.
The veteran defenseman passed a concussion test, but the headaches continued, Holmgren said.
Pronger has been rehabbing from knee surgery; he has missed the last eight games and hasn't played since a 6-4 loss in Winnipeg on Nov. 19.
"I talked to him after the game in Winnipeg, and he said he didn't feel great," Holmgren said. "It's a very loud building. He didn't feel like himself. We got him checked out after that game . . . and then, obviously, the dominoes started to fall with his knee and then this other stuff. We said a virus because we weren't sure what we were dealing with."
As for his surgically repaired knee, Pronger had some fluid removed a few days ago and has made strides, Holmgren said.
"His knee is actually doing great right now," Holmgren said. "I think he was on the right timetable for coming back from the arthroscopic surgery."
Like Pronger, Schenn has had an injury-plagued season. His has included a shoulder problem, a broken foot, and a concussion. He apparently suffered the latest injury when hit by Phoenix's Raffi Torres last Saturday. Since then, he has experienced "off and on" headaches, he said, but has noticed improvement the last few days.
"I'm just going to keep positive, and hopefully it'll turn around eventually," Schenn said of his season.
There is a chance Schenn will resume skating next week, Holmgren said, adding that the center's head injury seemed less severe than Pronger's.
Contact staff writer Sam Carchidi at firstname.lastname@example.org or @BroadStBull on Twitter.