Manager Andy Green confirmed Cosart will start Thursday's game against the Brewers.
Cosart will get the nod Thursday in place of Trevor Cahill, who was placed on the 10-day disabled list with a shoulder strain Wednesday. He's already tossed a pair of games for the Padres this season, allowing three runs (one earned) with a 4:3 K:BB through 7.2 innings of work. He'll line up against Zach Davies and the hot-hitting Brewers.