McGough will start the second game of Saturday's doubleheader against San Diego, Steve Gilbert of MLB.com reports.
Saturday will mark the first start of McGough's major-league career. He's put up a 4.76 ERA and 1.25 WHIP alongside a 69:24 K:BB through 56.2 innings on the season and will likely remain in the game for an inning or two before handing it off to the bullpen.