Sears was optioned to Triple-A Scranton/Wilkes-Barre following Wednesday's extra-inning win over the Reds.
The left-hander was called up by the Yankees in early July and covered 3.2 frames in long relief Wednesday after starter Luis Severino was removed with a shoulder injury. Sears had given up only one run across 15.1 innings entering the contest, but Cincinnati scored two runs against him. The 26-year-old could be an option to step into the rotation should Severino be forced to miss any time.