Winning the Heisman Trophy is never a guarantee of success in the NFL.
We've seen countless examples that just because you're the greatest player in college football doesn't mean you will get you name called early on draft day.
Look at Eric Crouch, Charlie Ward, Chris Weinke, Jason White and Troy Smith. All were Heisman Trophy winners but were taken in the later rounds of the draft and have shown none of the excellence on the field that won them that Heisman.
We see in 2011 that we have several Heisman candidates who should be more worried about Draft Day than winning that Heisman.