First off, what's the source on this?

Second, I'll believe Lopez-Vazquez as an undercard fight when I see it. Why would Arum put that on as an undercard fight for Cotto-Margarito II? Cotto-Margarito II will be a big moneymaker regardless of whether or not there's a good undercard fight, and Lopez-Vazquez is good enough to make money as a main event on its own.