Updated: 7:32 p.m.
NEW YORK - Nolan Patrick will miss the Flyers' Oct. 4 season opener after being diagnosed with a migraine disorder.
The 21-year-old center had been doing solo work on the ice but hadn't participated in training camp practices or played in any of the team's preseason games.
He remains week to week.
Here is a statement Thursday afternoon from general manager Chuck Fletcher:
After consultation with the Flyers' medical staff and with specialist Dr. Jeffrey Kutcher from the University of Michigan, forward Nolan Patrick has been diagnosed with migraine disorder. Patrick will not be going to Europe and we will provide additional information once the team returns. He will not be ready to start the season and is listed as week to week.
Going back to when he was drafted second overall in 2017, Patrick has battled injuries, including a sports hernia issue, concussion and other upper-body ailments.
Patrick reached out to the Flyers in June about his concerns and the team worked with him throughout the summer.
"Without getting into all the details, there were times this summer he felt great and there were times he didn't feel great," Fletcher said Thursday night at Madison Square Garden. "That was kind of the confusing part of it from a medical perspective."
Are the migraines connected to previous hits?
The doctors don't believe so. I can't fully speak for the doctors. Clearly at the end of last season, he took a slap shot in the neck area, back of the head area, in Long Island. He felt good after that and some time in the summer, he let us know that he was having headaches from time to time. It wasn't constant. We've spent time, Nolan spent the time, trying to get to the root of it. I think we feel comfortable now that it's a migraine issue. It's not a concussion, according to the doctors.
Nolan does have a history of migraines, going back to when he was younger - he had some in minor hockey, in junior hockey. There's a family history, as well. I think at this point, he feels relieved to know what it is. It's been periodic migraines and cluster headaches throughout the summer and I think he was concerned and we were concerned. The doctor feels that there's a regimen you can put him on and with medication, we can control the situation and we're hopeful.
Fletcher said there's "a whole host" of things that can help with treatment.
"I'm not 100 percent sure," Fletcher said. "I know there's medication, there could be some dietary things. ... I don't want to speak too much because I don't know that I have all the answers.
"He's taking the medication now. We're hoping that settles down the migraines and gets him to feeling 100 percent from a health perspective. And then after that, he's skated a bit, but he's essentially missed all of training camp. He hasn't played games, he hasn't been in any battle drills, and we're going to have to make sure we get him the conditioning work that he needs.
"Hopefully by the time we get back from Europe, we'll have a better sense of where he's at from a health perspective. And then from there, all going well, it's just a matter of conditioning.
"We consulted a lot of different people and I think we feel we're in a good place medically and we'll hope for the best."
The Flyers' roster is at 27 players.
Morgan Frost (injured)
Nolan Patrick (injured)
Tyler Pitlick (injured)
James van Riemsdyk
Andy Welinski (injured)
Click here to download the MyTeams App by NBC Sports! Receive comprehensive coverage of your teams and stream the Flyers, Sixers and Phillies games easily on your device.