Both men are veterans of The Ultimate Fighter (TUF) reality show, with Ferguson winning season 13 and Rio losing in the preliminary round of season 15.
Ferguson (13-3) has not competed since May 2012 when Michael Johnson defeated him by unanimous decision. The loss snapped a six-fight win-streak for "El Cucuy" and marked the first time he failed to win a fight since Oct. 2009.
Entering the fight off the longest layoff of his professional career, Ferguson will look to regain the form that allowed him to start his Octagon career 3-0.
Rio (9-2) is coming off his first official UFC defeat at the hands of Francisco Trinaldo at UFC on FX 8 last May. The 32-year-old is 1-1 with the organization and has yet to be knocked out in his mixed martial arts (MMA) career.
Ferguson vs. Rio is likely to take place on the preliminary portion of the UFC 166 fight card, which airs on FOX Sports 1 and Facebook. The main card will be available on pay-per-view (PPV) from the Toyota Center in Houston.
UFC 166 is headlined by a heavyweight championship trilogy bout as Cain Velasquez puts his title on the line against Junior dos Santos in what will be the third meeting between the two in less than two years.
For more news and notes on "Velasquez vs. Dos Santos 3," visit our complete event archive here.