If he does, then I'd be inclined to believe the Hep rumors. Why else would he avoid fighting in the US?
Maybe more than you think; speculation at japanese mma site kamipro.com (although I can't read japanese, this is what I've been told), DREAM may be ruined if it doesn't raise its ratings to about a 10%. And, they aren't paying fighters who have no way of effectively sueing them for it, namely Nick Diaz. http://mmamania.com/2008/08/02/nick-diaz-camp-wants-kj-noons-but-will-settle-for-hayato-mach-sakurai/