VerHagen was optioned to Triple-A Toledo on Saturday, MLive.com reports.
VerHagen is expected to join the Mud Hens' rotation. The 26-year-old underwent thoracic outlet syndrome surgery on his shoulder last July, and he's still working his way back to full strength. VerHagen struggled before the surgery last season, but he posted a 2.05 ERA across 26.1 MLB innings in 2015 and could get the call sometime this season if he pitches well in Toledo.