Williams will start Sunday's game against the Cardinals, Maddie Lee of NBC Sports Chicago reports.

EDGE Analysis

Williams was expected to pitch out of the bullpen until the All-Star break, but he'll take the mound to begin Sunday's series finale after Jake Arrieta (hamstring) was placed on the injured list Wednesday. The right-hander served as a bulk reliever Tuesday and allowed seven runs (three earned) on six hits and a walk while striking out three in 3.2 innings.