Lopez's scheduled start Sunday against the Royals was postponed due to inclement weather, Joel Goldberg of FOX Sports Kansas City reports.
The two teams will make up the contest as part of a day-night doubleheader April 28. The White Sox haven't announced how the postponement will affect their rotation plans, but it's likely that Lopez will simply be pushed back a day and take the hill for the first time this season Monday in Toronto, setting himself up for a two-start week.