Houston Astros rookie Tatsuya Imai is headed back to Houston for medical evaluation after experiencing right arm fatigue following his third major league start. The 27-year-old right-hander lasted just one out in Friday's 9-6 loss to the Seattle Mariners, allowing three runs on one hit while walking three batters and hitting another in 37 pitches.

Imai signed a $54 million, three-year contract this offseason and entered the season with high expectations. Through 8 2/3 innings, he sports a 7.27 ERA with 11 walks and 13 strikeouts. Manager Joe Espada said Imai expressed arm fatigue after the game, prompting the decision to send him home for examination by team doctors.

The timing is particularly challenging for the Astros, who are already dealing with pitching injuries. Right-handers Hunter Brown and Cristian Javier are both on the injured list with shoulder strains. To fill the rotation gap, Houston recalled 29-year-old Jayden Murray from Triple-A Sugar Land, who brings a 1.50 ERA in six innings of relief work.