The Marlins optioned Garrett to Triple-A Jacksonville on Sunday, Jordan McPherson of the Miami Herald reports.
Miami's decision to demote Garrett is likely more of a roster-management move rather than a result of any dissatisfaction with his performance; the 23-year-old lefty submitted the best start of his MLB career in Saturday's 3-2 win over the Padres, working seven innings while allowing only two runs and striking out 10. The Miami rotation is extremely shorthanded at the moment, so Garrett likely won't have to wait long for a call-up. The Marlins play only five games during the upcoming week, with the pair of off days allowing the club to get by with a three- or four-man rotation in the short term.