Rodgers guided the Packers to a historic Super Bowl victory over the Pittsburgh Steelers in Super Bowl XLV, was named Super Bowl MVP and has led his team to an incredible 13-1 record thus far this season. And he's having a monster MVP-type season (40 TDs, 120.1 passer rating) to boot. Who else accomplished more than Rodgers in 2011?
As for Sports Illustrated, they chose legendary college basketball coaches Mike Krzyzewski and Pat Summit as co-Sportsman of the Year. Personally, I have no problems with that. SI has a different criteria when picking their Sportsman of the Year. Sometimes their choice is not just about what an individual did on the field of play in that particular year. They also take life achievements (in any aspect of sports) into consideration. In the past they've chosen (the likes) of Dean Smith (1997); Don Shula (1993) and Arthur Ashe (1992) for their career achievements and/or philanthropy.
But if you're choosing an "ATHLETE", there is no question Rodgers is the obvious choice in 2011.
UPDATE (12-22-11): The Green Bay Packers are the new "America's Team". Read here.