The Royals have won three of their first four Cactus League games.
Duffy, the Royals' likely Opening Day starter, gave up three hits and two runs over 1 2/3 innings in his spring debut. Brewers right fielder Domingo Santana gave the Brewers an early lead with a single to score Keon Broxton, who had led off the bottom of the first inning with a triple. In the second inning, Duffy surrendered a solo homer to Brewers bench candidate Yadiel Rivera that banged off the batter's eye.
Duffy likely will throw once more before leaving March 9 to the join the United States team in the World Baseball Classic.