They have questioned the big man's heart. They watched him battle Chris Byrd -- the big man's biggest fight -- and despite winning on all three scorecards, when the bell rang for the 10th round the big man did not come out. Why? It was a torn rotator cuff, said the big man after the fight. The pain was unimaginable. How bad? So bad he could have done permanent damage. I mean, why else would he quit when he was winning?

"Hogwash," said the critics from their cozy ringside seats. The big man abandoned ship. He deserted the troops. He didn't have heart, they said, and within the Sweet Science that is far worse than having no chin, no style, or even no talent. It is sacrilege.

They are, however, very wrong. Big man Vitali Klitschko's heart is in perfect proportion to his 6-8, 245-pound frame. Not sure? Spend some time with him. Not three minutes during a press conference, but real time -- between takes at a photo shoot, training at Universum gym, over dinners of steak and fish and dark beer at his favorite Hamburg restaurant -- and you will understand. Heart is about caring, and Vitali Klitschko cares. He cares enough to be a loving husband and father, a mentor and best friend to his brother Wladimir. He cares enough to struggle for a PhD and master three languages. He cares enough to dedicate his time and energy to UNESCO; improving the lives of impoverished children across the globe. Don't believe it? Speak to him about Chechnya or global warming or Plato's Republic and you'll see the light in his eyes, and the more he talks -- mind you, it could be hours -- the more those brown orbs will widen and glow.

But here's the catch; as the conversation turns to boxing, the light does not turn to fire. There is no gleam that speaks of a desire, a desire greater than the man himself, to become champion. That's not to say he isn't a skilled practitioner -- the elder Klitschko has dispatched 31 of his 33 opponents via knockout including seasoned tough men like Herbie Hide and Larry Donald. But in boxing you cannot just WANT to win, like an attorney trying an important case. You must need to win. Your entire being must depend upon it, like an insatiable hunger with only one cure.

As Vitali clears plate after plate of food, an argument can be made for his 'hunger' of the literal sort, but a true hunger, that hunger that creates great fighters, has been sated by other outlets, outlets outside of the ring. On Saturday night he will step into the ring against Lennox Lewis, a man still hungry to solidify his reputation as the best heavyweight of the generation. Klitschko will fight with valor and heart and he will lose.

Fortunately it will not break him, because he isn't defined by who he is as a fighter, he is defined by who he is as a man. The upside is that because of who he is, because of his kindness, his caring, his heart -- the world will be a better place. The downside is that because of who he is, he will never be heavyweight champion.

Tim Struby is a regular contributor to ESPN Magazine. He has written articles on the Klitschko brothers and Roy Jones.