It might be that Gray is usually called upon to set screens. Or maybe it's that he's a big, dopey stiff who sucks. Whatever the case, it's probably not because he's white.
Via Marginal Revolution, a BYU economics professor has written a paper on how interracial bias does not exist in the passing patterns of NBA players. This, according to the abstract, demonstrates that "high levels of interracial cooperation can occur in a setting where workers are operating in a highly visible setting with strong incentives to behave efficiently."
Still, though, I'd like someone to do a study proving that Dominican position players in baseball hit and field better in support of Dominican pitchers. Because you know they do. It's all part of their grand plan to eradicate the white man from baseball.