this isn't the first time Barnett has had problems with this. If I remember correctly he was stripped of his UFC title after testing positive for banned substances.
Anyway, as for who Fedor should face... I really thought Barnet was his best opponent. I don't seeing anyone else posing much of a problem for him. I wouldn't mind watching him beat down Belfort. Who knows Belfort could get a lucky punch. He has very fast hands.