Multiple sources confirmed to ESPN discussions are in place for the immediate rematch. UFC 200 will take place at the newly built T-Mobile Arena.
MMAFighting.com first reported the matchup.
Diaz (19-10) handed McGregor the first loss of his UFC career earlier this month, when he submitted the featherweight champion via rear-naked choke at UFC 196. Diaz, who fights out of Stockton, California, accepted the fight on 11 days' notice after McGregor's original opponent, UFC lightweight champion Rafael dos Anjos, pulled out with a broken foot.
Earlier this week, Diaz told ESPN.com he wasn't happy with the excuses many have made for McGregor's loss. McGregor (19-3) technically moved up two weight classes for that fight. He is still the champion at 145 pounds but agreed to face Diaz at 170 because the fight took place on short notice. The original matchup against dos Anjos had been slated for 155 pounds.
UFC president Dana White has said the first bout between McGregor and Diaz produced about 1.5 million pay-per-view buys. It is also produced an $8.1 million gate at the MGM Grand Garden Arena in Las Vegas, the third highest in company history. McGregor has headlined two of the top three highest-producing gates in the UFC.
The UFC has not officially confirmed the rematch. It is unclear whether McGregor will vacate the 145-pound championship he won in December by knocking out former champion Jose Aldo in 13 seconds. Immediately after the loss to Diaz, McGregor had said he would go back to 145 and defend the belt against either Aldo or Frankie Edgar.