The game will be played July 12 in Detroit.
Rodriguez had compiled 613,218 votes and had a lead of more than 400,000 votes at his position over Bill Mueller of Boston.
Other position leaders in the American league were Boston catcher Jason Varitek (425,878 votes), New York first baseman Tino Martinez (347,501), Baltimore shortstop Miguel Tejada (504,499) and outfielders Manny Ramirez (553,959) of Boston, Vladimir Guerrero (542,541) of the Los Angeles Angels and Ichiro Suzuki (515,343) of Seattle.
Boston's David Ortiz was out front among designated hitters.
National League voting will be released Wednesday.