Joe Randa drove in a pair of runs for the Royals, who built a 10-1 lead after three innings.
Kansas City welcomed back injury-plagued lefthander Jose Rosado, who made his first appearance against an opposing team since last year's spring training. He pitched two innings and allowed three hits, including a leadoff homer to Todd Walker.
The Royals went ahead with three runs in the first on McCarty's sacrifice fly and Randa'a two-run single.
Cincinnati third baseman Brandon Larson, a non-roster invitee, had two hits.