The Athletics recalled O'Loughlin from Triple-A Las Vegas on Tuesday.
The A's sent O'Loughlin to the minors June 9 after he had thrown seven shutout innings across three appearances out of the bullpen. He has since started two Triple-A games, allowing six earned runs in just 7.2 frames. He'll likely return to a multi-inning relief role while in Oakland, taking the place of Aaron Brooks on the MLB roster.