Butler, who hit .406 (13-for-32) with two doubles, five home runs and 12 RBIs in seven games, is sharing the award with the Angels' Ervin Santana, who threw a no-hitter on Wednesday against the Indians.
The home runs for Butler came on four consecutive days, a career best for the 25-year-old. Butler finished a triple shy of the cycle on Tuesday, going 3-for-4 with three RBIs in a high-powered offensive game that Kansas City dropped, 13-9, to Boston. Butler's hitting was the difference two days later, as his three-run homer played a big role in the Royals' 4-3 win over the Red Sox.
Butler unleashed two more home runs on Friday in Cleveland, the fifth multihomer game of his five-year career, and his first since September 2009. Butler won the weekly award twice before, in August and September 2009.
On the season, Butler has a .295/.376/.455 line, with 12 home runs and 53 RBIs.