At a press conference following Saturday's UFC on FUEL event, UFC president Dana White confirmed that the date is no sure thing. In trying to finalize the show -- originally scheduled for June 23 -- the UFC has come up against some resistance because Rio happens to be hosting a United Nations Conference on Sustainable Development during the same week.
"The problem is, they don't like the idea of us coming the same time this United Nations convention is going on," he said. "The other problem is hotel rooms. Most of the hotel rooms are being taken up. And we don't think, we know that the Anderson Silva-Chael Sonnen fight is one of the biggest sporting events this year, in the world."
The UFC is expecting to run their event at Estádio Olímpico João Havelange, a soccer stadium which will likely hold around 55,000 people when reconfigured for MMA.
The UN conference is a three-day affair which takes place from June 20-22. The event's website does not estimate an attendance for the conference, saying it will draw "thousands," but does list 194 member nations. That conflicts greatly with the UFC's hope of taking over the city that week for Silva-Sonnen.
"I think it’s a huge sporting event," he said. "I think people will come to Rio from all over the world. I think we're going to need hotel rooms. Hopefully we’ll get this thing done the next few days, one way or the other."
The first Silva-Sonnen fight took place in August 2010, with Sonnen controlling the action for the first four-and-a-half rounds before Silva trapped him in a fight-ending triangle choke to retain his UFC middleweight championship.