The Astros recalled Martinez from Triple-A Sugar Land on Tuesday.
Martinez will join the 26-man active roster as a replacement for right-hander Jake Odorizzi (lower leg), who was placed on the 15-day injured list one day after exiting his start against the Red Sox. The 27-year-old right-hander has previously made two relief appearances for Houston this season, covering 2.2 scoreless frames in total while striking out four hitters.