And now that I have downloaded the regulations from FIFA’s website, maybe not. There is a provision for replacing players prior to qualifying matches, but the wording is not specific as to whether it applies to the World Cup proper.
I may stand corrected :)
I’m on a couple of other sites trying to research it now; and given that I don’t (yet) see a raging debate about Donovan or not; I’m gonna guess your original point stands.