Infante finished the month with 19 RBIs, highest ever by a Royals second baseman for the season's first month, surpassing 14 by Cookie Rojas in 1973 and Bip Roberts in '96.
Shields won his last three starts in April, all on the road. He also posted a 2.03 ERA, held opponents to a .196 average and had 41 strikeouts.
The top player is selected in a vote of media and fans, while the pitcher is picked by media only.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.