Valdez was optioned to Triple-A Buffalo on Friday, Shi Davidi of Sportsnet.ca reports.
Valdez, along with Dwight Smith, was sent down in order to clear roster space for Josh Donaldson and Troy Tulowitzki, both of whom are returning from injury Friday. The 32-year-old right-hander, claimed off waivers from Oakland earlier this month, pitched one scoreless inning for the Blue Jays but will make his next appearance in the minors, where he has a 3.00 ERA through two starts this season.