Merrifield went 2-for-5 with a grand slam and a double in Wednesday's loss to Houston.
The second baseman's long ball with the bases loaded in the seventh inning gave the Royals a two-run lead, but the Astros rallied and eventually pulled out the win. Merrifield's homer was his first since June 30 -- a span of 47 games. However, he racked up 15 thefts over that span and ranks second in the majors with 37 stolen bases on the season.