A year and half later, Silva and Vera to rematch May 15th

On January 1st, 2011 Brandon Vera and Thiago Silva fought at UFC 135, with the Brazilian stopping Vera in the 2nd round by punches. It was Vera's 3rd loss in a row and he was subsequently released by the promotion.
It was a few laters that we learned that Thiago Silva had tested positive for an anabolic agent and the bout was subsequently changed to a no-contest. With the result changed, the UFC welcome Vera back to the UFC, seeing as how he had only lost to an opponent that cheated.

Vera returned to the UFC in October of 2011, winning a unanimous decision over Eliot Marshall. Silva however, received a stiff 1. yr suspension from the Nevada State Athletic Commission, as well as a $45,000 fine. That suspension ended in January of 2012, but it was unsure if Silva would return to the UFC.
Today the UFC announced that Thiago Silva would indeed return, and his comeback match he would have to give Brandon Vera a rematch:

Light heavyweights Thiago Silva and Brandon "The Truth" Vera have verbally agreed to wrap up some unfinished business this May in Fairfax, VA. "Their last fight ended up a no contest and both guys are out to prove that they are the better man," said UFC president Dana White.

source: ufc.com