The Cubs optioned Megill to Triple-A Iowa on Wednesday, Gordon Wittenmyer of NBC Sports Chicago reports.
The move was necessary to make room on the roster for Wednesday's spot starter Robert Stock. Megill has yet to allow a run in 2021, albeit in just three innings of relief work, so it wouldn't be surprising to see him back on the big-league roster in the near future, perhaps in the coming days if Stock's start isn't spectacular.