Olson left Thursday's 5-4 loss to the Mariners in the sixth inning with right hand pain, Jane Lee of MLB.com reports. He went 1-for-2 with a run scored before departing.
The Athletics aren't likely to provide an update on the severity of Olson's injury until he's re-evaluated in California when the team arrives back from Japan. According to Susan Slusser of the San Francisco Chronicle, Olson experienced the pain in his hand after fouling off a pitch and had difficulty gripping the bat, which suggests his injury may be more than a day-to-day concern. If Olson is forced to miss time, Mark Canha or Chad Pinder could be in line for more action at first base.