Paulo Filho and Chael Sonnen are finally set to rematch on September 10th. The two were originally scheduled to rematch on March 26th in order to settle a disputed Filho win at UEC 31 back in December.
In that fight, Sonnen appeared to be controlling the action well into the second round before Filho caught him in an armbar. Sonnen did not appear to tap, but yelled while the armbar was secured causing the referee to stop the fight via verbal submission. Sonnen disputed the stoppage and called immediately called for a rematch which was eventually granted for March 26th.
However, Filho was unable to make weight for the fight and was purported to be suffering from chemical dependency and depression according to his management, who declared Filho ready to fight now. Link