Martin received an invitation to the Astros' major-league spring training, Jake Kaplan of The Athletic reports.
Martin quickly received a promotion after starting the season at High-A Buies Creek, and posted a 2.97 ERA, 1.09 WHIP and 96:28 K:BB over 103 innings with Double-A Corpus Christi. The 22-year-old seems unlikely to make the Astros' Opening Day roster though a promotion to Triple-A early on in 2019 wouldn't be surprising.