Roy was recalled from AHL Laval on Tuesday.
Roy's promotion comes as Owen Beck was sent down in a corresponding move. The 22-year-old Roy will join the Habs for their four-game road trip and could get into the lineup if Kirby Dach (lower body) and Patrik Laine (lower body) remain on the shelf. If either of that duo plays versus the Flames on Wednesday, it likely will mean Roy is playing the role of healthy scratch from the press box.