Though the fight is being looked at for the April 25 date in Montreal, the report said it wasn't yet a done deal.
Barao and Dillashaw fought at UFC 173 in May 2013, which went down as one of the most memorable fights of the year. The 135-pound champion Barao came in with a 32-fight unbeaten streak, and was a heavy favorite to beat the Team Alpha Male fighter Dillashaw. Instead, Dillashaw hurt Barao early, dominated him throughout, and finished the fight in the fifth round via TKO (head kick and follow-up punches).
The two were slated to have a rematch at UFC 177 in August, but Barao had to cancel only a day beforehand after an incident during his weight cut. Dillashaw ended up defending his title against Joe Soto, who was originally scheduled to fight on the undercard.
Also being looked at for UFC 186 is the return of Quinton Jackson. UFC Tonight reported that talks are underway for a fight between "Rampage" and Fabio Maldonado, who is coming off a TKO victory over Hans Stringer at UFC 179.
Jackson last fought for the UFC at UFC on FOX 6 in 2013 against Glover Teixeira, a bout he lost via unanimous decision. He won three straight while fighting for Bellator, including a victory over Muhammed Lawal at Bellator 120, the promotion's one and only pay-per-view event.
Though the fight is being discussed, the report said it's not a done deal. With Bellator contending that Jackson is still under contract, there are contractual hurdles to work through for him to appear inside the Octagon.
UFC 186 will take place on April 25 at the Bell Centre in Montreal, Quebec, Canada.