Oh I see, well in that case, going by KM's link there, Nani has more successful dribbles, far more key passes, more successful crosses, a slightly lower pass completion ratio, and pretty much the same passes per game, yet he's 10 ranks lower.
The general consensus however is that Nani has been the worse player, something I agree with, but it just shows that stats aren't everything and to be using them as a basis for Valencia being one of our better performers is a bit dumb.
From watching all our games I think he's been poor, and in the end, it's from watching the games themselves that we should draw our conclusions, not stats.