The Astros recalled Martinez from Triple-A Sugar Land on Saturday, Matt Kawahara of the Houston Chronicle reports.
He'll provide a fresh arm to the Houston bullpen after Ryan Pressly was placed on the 15-day injured list in a corresponding move due to a lower-back strain. Over his 41 appearances with Houston before he was optioned to Sugar Land on July 31, Martinez posted a 2.92 ERA and 1.22 WHIP across 49.1 innings.