This fight card in an exemption since the main event is the fight that everybody in the boxing world wants to see.
Arum apparently isn't to keen on making this fight happen, he apparently turned down an offer for Margarito to fight Martinez in a rematch. And so all the pieces fall into place, he gets Texas Stadium before Mayweather even is called, he turns down a big time rematch for Margarito. Arum is pretty much ready to announce Pacquiao-Margarito the second he can cut out on negotiations.
I've read Arum reserved the MGM Grand (Vegas) and Cowboys Stadium (Texas) for the November 13 date. He also said he'll try his best to make the Pacquiao-Floyd fight.