In six games last week, Ellis led the AL with a .571 (12-for-21) batting average and 11 RBIs while notching three doubles, a home run and 19 total bases. The seven-year veteran also posted a .857 slugging percentage and a .542 on-base percentage.
His breakout game came on Tuesday against the Orioles when he set a career-best by going 5-for-5 with a season-high four RBIs to help lead the A's to a 9-1 win.
Ellis, who has been with the A's since 2002, became the first second baseman in A's history to go 5-for-5 and the 18th in club history to accomplish the feat.
Ellis also had a big game Sunday when he hit a two-out, walk-off home run in the bottom of the ninth against the White Sox to give the A's a 3-2 win.
The 32-year-old enters Monday currently batting .283 on the season with 15 doubles, six home runs, 42 RBIs, 34 runs scored and six stolen bases.
Other noteworthy performances for the week included Yankees shortstop Derek Jeter, who led the AL with 14 hits and broke the all-time record for most career hits by a shortstop, and Boston Red Sox left fielder Jason Bay, who led the AL with four home runs. Also considered were Rangers center fielder Josh Hamilton and Twins right-hander Scott Baker.
For winning the award, Ellis gets a luxury Swiss watch from Tourneau, the world's largest watch store. It's the first time he has won the weekly award in his career.
Rhett Bollinger is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.