Some people already said it. Let me try to summarize what I believe is the wisest way to descibe Nadal as a grass court player: * his great topspin is not that effective on grass. * his defensive skills, where he stands so far behind the baseline (including when he hits return of serve), is not that effective om grass. * his twisted serve is not that effective on grass (he does not have a very good flat serve). Some people want to compare him to Hewitt. They say: if Hewitt can play on grass, the Nadal should be able to do it. Its not really true. Hewitt is a good example of the modern contrapunching grass court player. He can take the ball very early and re-direct it (nadal can not handle the speed that well). Nadals defensive skills is more based on the fact that he stands far behind the baseline (which is not possible on grass). Hewitt can react very, very fast. Even faster than Nadal. Thats why he can handle the grass better. Also:he hits the ball flat while Nadal hits the ball with heavy spin. Hewitt then, I would argue, is a little bit more of a natural grass court player, just as Nadal is a far more natural clay courter than Hewitt. Nadal is capable of becoming a very good grass court player I think. But I doubt he will become one of the top 10 best grass court players in the world.