Schreiber was optioned to Triple-A Toledo following Tuesday's loss to the Mariners, Evan Woodbery of MLive.com reports.
Schreiber had his contract selected from Triple-A last week and allowed three runs on four hits with two walks and two strikeouts over his first 1.2 big-league frames. The 25-year-old returns to Toledo, where he has a 2.83 ERA, 1.19 WHIP and 59:20 K:BB over 47.2 innings.