Mondesi is out of the lineup Sunday against the Twins, Jeffrey Flanagan of MLB.com reports.
The Royals promoted Mondesi to the big leagues in late July with the hope that he could provide some stability at second base after Whit Merrifield fell into an extended slump, but the 21-year-old has unsurprisingly experienced some growing pains. He's hitting just .196/.211/.250 with four stolen bases across 60 plate appearances since his call-up. Mondesi will be replaced in Sunday's lineup by Christian Colon and could soon be headed back to Triple-A Omaha if he doesn't turn things around quickly.