That's the rumor according to Nogueira's muay thai coach Luiz Aves:
According to Luiz Aves, Nogueira’s Muay Thai coach, this fight can happen. "It’s not 100% yet, but Rodrigo might fight in December. When I was in the US, I heard some rumors that he could face Napão (Gonzaga)… It’s not right yet, but I heard that he could fight him, then would move forward to the title. I think, by the middle of 2010, we’ll fight for the title again", revealed Alves.
This fight wouldn't make any sense to me, not to mention that it's being reported that Nogueira will fight for the title next. The December card is already shaping up pretty good and adding Nogueira/Gonzaga to it wouldn't add anything extra in regards to PPV buys. Gonzaga has already lost to Carwin, and hasn't beaten anyone of note since Cro Cop was Cro Cop. So I'd chalk this up to not happening, but I've seen crazier things happen before.