That normally would be left-hander Will Smith's spot, but he was moved from Friday night to Game 1 of Saturday's doubleheader, so he wouldn't have the normal four days of rest by Wednesday.
Manager Ned Yost said no decision has been made on that. It'll depend on how the next few games go. Current relievers Everett Teaford and Vin Mazzaro have started games for the Royals this season. With rosters expanded in September, a Minor League pitcher also could plug the gap.