Arroyo is Puerto Rican and looks like he may be a quarter black and Najera may be part Indigenous Indian, but I would personally consider them white. I consider someone who is a quarter Native American/three quarters white or so to be white.
If you are a quarter black the caste system immediately claims you as "a black athlete" so in the later circumstance given the circumstances I wouldn't consider them white if they are AMERICAN.
I have noticed the "one dropping" rule applies less so with the Hispanic part blacks; for instance from my research (I couldn't get a definite though) Brock Lopez is a quarter black. His father was a half black Cuban I believe, but most people consider him a white Hispanic because he looks pretty white, has the name Lopez and seems to identify with white culture.
Anderson Varejao is Brazilian and looks pretty dark so I don't think he is labeled white by fans. A guy like Hammedi the Iranian Center of the Grizzlies; probably doesn't consider himself white, only an Iranian b/c he doesn't want to be associated with liberal Euro culture.
So I basically label an athlete however the caste system labels them and they label themselves. Realistically using this format, I think the NBA should be just under 60% white.
I'd break it up maybe 55-60% white, 25-30% black, 9-10% Asian (believe me the Chinese have gotten interested and are a large demographic group), 5-6% Mestizo Hispanic /Middle Easterner/Pacific Islander/Other.
Again, sorry for giving too much details but I wanted to break down what the percentages of other races should be in a fair world too.