Legare was recalled from AHL Utica on Thursday.
Legare's promotion comes as Zack MacEwen (lower body) was designated for injured reserve in a corresponding move. With Cody Glass (undisclosed) also banged up, the 24-year-old Legare may be pressed into service against the Capitals on Saturday, though Juho Lammikko will also be in the mix for a spot in the lineup.