Corbin Martin headed to the Major Leagues earlier this year, but now he's going on the seven-day injured list.
The fourth-ranked Astros prospect left Sunday's start after four innings with elbow discomfort and went to Houston to be evaluated by team doctors.
"He came out and didn't feel right with his elbow, so we brought him to Houston and he's being evaluated," Astros president of baseball operations and general manager Jeff Luhnow told MLB.com. "We're currently waiting for diagnosis and figure out what we're going to do."
2019 MiLB include
MLB.com's No. 48 overall prospect appeared in five games for Houston this season, going 1-1 with a 5.59 ERA and 19 strikeouts before being sent down to Triple-A on June 4. He was called up to The Show for the first time on May 12.
In two stints with the Express this season, the 2017 second-round pick posted a 2-1 record with a 3.13 ERA over 37 1/3 innings, striking out 45 while putting up a 1.37 WHIP.
Prior to exiting Sunday's game, Martin allowed three runs on six hits while striking out five against Iowa.