The Angels optioned Johnson to the minors following his start Friday versus Milwaukee, Michael Huntley of MLB.com reports reports.
Johnson took the loss Friday, allowing five runs over 4.1 innings. He also struggled in his previous start, when he gave up a season-worst eight runs over 3.1 frames in a loss to the Giants. To fill Johnson's spot on the 26-man roster, the Angels summoned Brett Kerry from Triple-A Salt Lake.