Should heavy favorite Canelo Alvarez defend his WBC 160-pound world title against Amir Khan on Saturday night in Las Vegas, the stage could be set for a Sept. 17 mega-middleweight boxing title fight at AT&T Stadium.Alvarez (46-1-1, 32 KOs) could meet former champion Gennady Golovkin (35-0, 32 KOs) in what certainly will be billed as "the fight of the year."There is nothing currently on the AT&T Stadium calendar for the Saturday night before the Cowboys play a road game at the Washington Redskins.