Gallen was placed on the 10-day injured list with a right hamstring strain Saturday.
Gallen was removed from Friday's start against the Giants in the top of the third inning due to the hamstring issue. The right-hander described the grade of his strain as "very mild" and said that he wasn't in any pain Saturday, Zach Buchanan of The Athletic reports. However, he'll now miss his final start prior to the All-Star break following his placement on the injured list. The Diamondbacks haven't provided a timetable for Gallen's return, but he could have a fairly brief stay on the IL if he remains without pain.