it would be in the Padres best interest to lose Sunday. If the Dbacks win then the Braves/Mets have to play at least one game on Monday. I'm sure they would love their first round opponent to have to play one or two games on Monday, exhaust pitching, and travel accross the country to play them rested with their rotation set up on Tuesday.
Will they intentionally lose? I doubt it. Will they rest some starters? Absolutely.