• Past winners
The 21-year-old Mazara hit .283/.319/.491 with seven home runs and 17 RBIs in 27 May games. His seven homers on the month led all AL rookies and tied for most overall with Dodgers shortstop Corey Seager, while his 17 RBIs paced all Major League rookies.
Mazara had 11 multihit efforts during the month and is now hitting .299/.344/.471 with nine homers and 24 RBIs on the season.
Cash Kruth is a reporter for MLB.com. Follow him on Twitter at @cashkruth. This story was not subject to the approval of Major League Baseball or its clubs.