The Nationals optioned Machado to Triple-A Rochester on Tuesday.
Washington will swap Machado off the 26-man active roster for another right-handed reliever in Carl Edwards, who was called up from Triple-A in a corresponding move. Since breaking camp as a member of the bullpen, Machado has worked mostly in the middle innings for Washington while delivering a 2.45 ERA, 1.18 WHIP and 8:5 K:BB across 11 frames.