Martinez was recalled from Triple-A Sugar Land on Thursday, Danielle Lerner of the Houston Chronicle reports.
The right-hander was sent down by the Astros in mid-August but will rejoin the big-league club Thursday with closer Ryan Pressly (neck) heading to the injured list. Martinez has appeared in 23 MLB games this season and has a 2.48 ERA, 1.04 WHIP and 31:13 K:BB across 32.2 innings this season.