Ashby will start Sunday's series finale against the Giants in San Francisco, Todd Rosiak of the Milwaukee Journal Sentinel reports.
Jason Alexander had been listed as the Brewers' probable starter for Sunday, but the team will go with Ashby on three days' rest instead. The reason for the change was not immediately available. Ashby went 4.1 innings his last time out and has failed to complete five innings in four of his last five starts around an IL stint with left forearm inflammation.