The Reds designated Soto for assignment Tuesday, C. Trent Rosecrans of The Athletic reports.
Soto was moved off the 40-man roster after the Reds acquired right-hander Jakob Junis and outfielder Joey Weimer from the Brewers while sending right-hander Frankie Montas to Milwaukee. The 24-year-old Soto had gone hitless in three plate appearances during his brief time with the Reds this season.