Kidwiler Collection/Diamond Images/Getty ImagesWillie Mays poses at the Polo Grounds during his rookie season in 1951.Baseball legend Willie Mays turns 80 today. David Schoenfield of ESPN.com's Sweet Spot blog, from which I borrowed the above photo, has a piece arguing that Mays was the greatest ever, while John Shea of the San Francisco Chronicle catches up with Mays today. Happy birthday, Willie.