Hendriks (groin) exited Friday's loss to the Mariners after pitching to only one batter in the eighth inning, Jane Lee of MLB.com reports.
The right-hander gave up a base hit to Guillermo Heredia before gingerly walking off the mound. With the A's needing a spot in the bullpen for Ryan Dull (shoulder), expect Hendriks to land on the disabled list, but as yet there's no indication of the severity of his groin strain or how long he might be out of action.