Yarbrough (head) will start for Triple-A Omaha on Saturday.
Yarbrough's first rehab appearance came in an Arizona Complex League game Monday, and he allowed three runs on five hits and no walks with two strikeouts over three innings versus the White Sox's rookie-ball affiliate. The southpaw is not eligible to be activated until early July, so he's likely to have at least one additional outing in the minors beyond Saturday while recovering from multiple fractures in his head.