You notice they never said what his average speed was? They only using Bush's top speed to compare with Bolt's average speed. It have many men who could get to that speed but to hold it for any distance is what separates the Olympic sprinters from the rest. That is not to say that Bush may not have become a great sprinter if he had chosen track, but the comparison is just a bunch of sensationalist journalism.
Hard to gauge what Bush's "average speed" would be, since he's hardly ever running at top speed in a game... any "average speed" they attempt to offer would be deceiving. While he is capable of hitting top speed once or twice in a game (remember, hard to hit top speed consistently when man tackling yuh or you dodging them)... for him to hit top speed he needs the ball in his hands with lots of room to run. Not too many opportunities for that in a game.
I think we should just take the article in stride... it' s a fun kinda thing and one that is more about Bush's speed than any true comparison to Bolt.
Incidentally, there was a nice (albeit fun) piece done by Kenny Mayne yesterday on Sunday NFL Countdown...
http://www.youtube.com/watch?v=XEB8GK9zBQMShould we also start saying that they're silly for even mentioning Bolt and the NFL in the same breath? Nah man, just have fun with the thing... Usain name making it more and more into the American mainstream, track can only benefit from the ancillary publicity.