They would be in San Diego, which is all the more reason for the Padres to try to manipulate their series with the DBacks to make the doubleheader a real thing.
As for what MLB can do, it's tough to move wildcard series because fans have already bought tickets and potentially made travel plans. But for the teams it would be most convenient to move the NL wildcard series to Wed to Fri. 50/50 odds those series end on Thursday with Friday off anyway.