Right-hander Cesar Vargas, who was slated to pitch on Monday, will get the ball on Tuesday instead. That pushes Colin Rea to Wednesday, when he'll pitch Game 1, followed by Drew Pomeranz in Game 2.
Without an off-day until Monday, the Padres still need another starter -- presumably for Saturday's game in Milwaukee. Relievers Carlos Villanueva and Brad Hand both have plenty of starting experience.
It's the Padres' first rainout of the season and first since last July 19, against the Rockies in San Diego.
AJ Cassavell covers the Padres for MLB.com. Follow him on Twitter @ajcassavell. This story was not subject to the approval of Major League Baseball or its clubs.