The Royals placed Yarbrough on the 15-day injured list Monday with head fractures.
Yarbrough took a line drive off the head in Sunday's contest with the Athletics, but he was fortunately able to walk off under his own power. That being said, he sustained facial fractures and will now be on the shelf for at least 15 days. The left-hander's true timetable to return is unknown, and the Royals will have to turn to another pitcher to replace him in the rotation when his next turn comes up Friday in Milwaukee.