The 2009 NBA draft was the third draft under the league's "one and done" rule, which requires an American player to wait a year following his class's graduation from high school before entering the NBA draft. The 2006 draft, the year Andrea Bargnani was drafted first overall, was the leap year between high school players entering the draft and the first class of "one and done players."

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For the NBA it is a business decision that protects its teams from drafting unproven high…