Lorenzo Cain, the usual center fielder, moved over to right field, and Yost indicated that backups Jarrod Dyson and Justin Maxwell will be used at the various outfield spots later.
Valencia was playing in place of sore-shouldered Omar Infante and Pedro Ciriaco was at shortstop for Alcides Escobar, who is on paternity leave.
As it turned out, Aoki handled two flyouts in center and Valencia took care of all three chances he had, including being the middle man in a double play.
There's the possibility that the Royals might break camp without a true middle infielder as a backup, although guys like Ciriaco, Christian Colon, Johnny Giavotella and Jason Donald are hoping that's not the case.
Regular third baseman Mike Moustakas has been taking ground balls at second base.
"Moose can do a lot of things. He can catch -- he was a high school catcher -- he can play third and he's OK at second. He turns two all right," Yost said.
"Just in case something happens, you're always sitting back and thinking, 'OK, what can we do?' Infante can play short, Moose can go to second, Valencia can go to third or Valencia can play second and we can leave Moose at third. This is where you do all of your experimenting, down here now."
There's also the possibility of playing first baseman Eric Hosmer in right field, where he's appeared previously in Interleague games.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.