Blanco was optioned to Triple-A Sugar Land on Saturday, Chandler Rome of The Athletic reports.
Blanco was called up for a spot start against the Mariners on Thursday, giving up three runs in six innings. He wasn't going to get into another game before the All-Star break, so he'll return to the minors to await his next chance. Joel Kuhnel was recalled to give the team another option in the bullpen.