Drysdale (upper body) was placed on injured reserve Wednesday, per CapFriendly.
Drysdale was already deemed week-to-week, so this move is simply to free up a roster spot for the Flyers. Egor Zamula has the most to gain from Drysdale's absence, as he'll likely absorb Drysdale's power-play ice time while featuring more consistently in the lineup in general.