Kuroda-Grauer was diagnosed with a testicular contusion after exiting Monday's 5-2 win over the Diamondbacks, Martin Gallegos of MLB.com reports.
The rookie went 2-for-3 with a base hit and a solo home run -- the first of his career -- before exiting the game prior to the bottom of the sixth inning with the injury. The Athletics haven't provided word on the severity of the injury, but he can be considered day-to-day heading into Tuesday's contest.