The Guardians optioned De Los Santos to Triple-A Columbus on Sunday, Mandy Bell of MLB.com reports.
De Los Santos wasn't going to be available for Sunday's series finale with Toronto after he worked an inning and tossed 30 pitches while giving up a run and walking three in Saturday's 8-3 loss in Game 1 of a doubleheader. As a result, the Guardians will swap De Los Santos off the 26-man active roster for Kirk McCarty, who was called up from Triple-A in a corresponding move.