This Saturday’s main event has been nearly two years in the making, which is how long odds have been available for Silva-Sonnen II.

Oddsmakers opened prices on the rematch immediately following UFC 117, but a positive drug test and venue changes have made for one wild ride for MMA bettors.

Anderson Silva opened as a -250 favorite over Chael Sonnen (+190) for their rematch (venue TBA, fight must happen before Feb. 6, 2011) after coming away with a last-minute submission win as a near -500 favorite at UFC 117 on August 7, 2010.

But when it was revealed Sonnen tested positive for high testosterone levels and was suspended briefly, books pulled the odds off the board in the third week of September 2010.

In the meantime, Silva takes a fight with Vitor Belfort at UFC 126 in February 2011 and is bet down from -350 to -195 with the public losing faith in the middleweight champ following his shaky outing at UFC 117. Silva burns his doubters with one of the greatest KO’s in MMA history, dropping Belfort with a front kick to the face in the first round.

Silva added another win to his resume, improving to 31-4, with a TKO victory against Yushin Okami at UFC 134 on August 7, 2011. Sonnen returns from suspension and climbs back to the middleweight division's No. 1 contender spot with victories over Brian Stann (via submission) and Michael Bisping (via decision).

Books rush to re-open the odds for Silva-Sonnen II, this time pricing the middleweight belt holder at -340. Much of that price was inflated due to speculation that the bout would be held in Silva’s home country of Brazil for UFC 147 on June 23, 2012.

However, scheduling conflicts with the UN Conference in Brazil force the promotion to bump the fight to UFC 148 at MGM Grand Garden Arena in Las Vegas. With the venue moving to the United States, bettors begin playing on Sonnen and dropped the opening numbers to as low as Silva -235/Sonnen +175.

Action heading into the weekend is beginning to lean toward the champion, pushing Silva back up to his current price of -275/Sonnen +215. Renowned MMA oddsmaker Joey Oddessa expects fight fans to start taking a shot on the live underdog and believes Silva backers will get a better price in the hours before UFC 148’s main event.

Other odds available include round props (which round will a fighter win), and method of victory, with Silva via TKO, KO or DQ priced as an even money favorite. Sonnen via decision is priced at +300 and Silva via submission is set at +275.