Rasmus Ristolainen, who missed his second straight game Tuesday night with an upper-body issue, was placed on injured reserve.
The 27-year-old defenseman has been considered day to day.
"He's feeling pretty good, but certainly not where we need him to be to be a player," Flyers interim head coach Mike Yeo said Monday. "You look at the way he plays, he's got to be feeling pretty good to go out there and play at that level and with that physicality."
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The Flyers have only six healthy blueliners on their roster, so the decision to put Ristolainen on IR opens up a roster spot for a potential call-up from AHL affiliate Lehigh Valley.
Cam York, one of the club's top prospects, is dealing with an injury that doesn't appear to be overly serious. If the 21-year-old is healthy, he's the clear-cut call-up for the Flyers.
After visiting the Penguins on Tuesday, the Flyers open an eight-game homestand Thursday when they host the Capitals (7 p.m. ET/NBCSP). The club then has three days before its next game.
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Ristolainen has been rehab skating and took part in a portion of Monday's practice.
The Flyers traded for the Finnish defenseman during the summer. He's on the final year of a six-year, $32.4 million contract.
"The goal when we traded for him was to keep him," Flyers general manager Chuck Fletcher said Jan. 26. "And obviously he's a pending UFA, he will control a lot of that discussion and we'll work with his representation to see what makes sense."
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