The Astros optioned Coleman to Triple-A Sugar Land on Thursday, Chandler Rome of The Athletic reports.
Coleman struggled heavily in the majors last season, posting an 8.84 ERA and 2.02 WHIP across 18.1 innings with the Royals. After being traded to Houston in December, Coleman's troubles have continued to plague him in spring training, and he will likely remain in Triple-A until a noticeable improvement is made on the mound.