We welcome all white potential NFL players. Of course, running a really fast 40 is great, but catching the ball is also important (critical if you're white), route running, beating jams, holding on to the ball when blindsided by a 100 kilo (speaking to someone outside the US) linebacker, etc.
Of course, if you're black and really fast, those other things aren't as important. Maybe, since nobody knows him over here, Joshua should get a really, really deep, dark tan. That will help him immensely.