Jon Jones will return from his positive test for cocaine and make the ninth defense of his
Jones (21-1) will fight Anthony Johnson, who surprised Alexander Gustafsson with a first-round knockout last month in Stockholm.
Additionally, unbeaten middleweight champion Chris Weidman (12-0) will make his delayed defense against veteran former champion Vitor Belfort.
Weidman required surgery on both knees following his July 2014, unanimous-decision victory over Lyoto Machida, then suffered a rib injury last month to scrap a scheduled Feb. 28 main-event fight at Staples Center against Belfort.
Belfort (24-10) was a UFC champion in 1997 and claimed a 2012 first-round submission victory over Johnson. He's been beaten in recent title shots, first, in 2011, by a highlight-reel kick to the face by then-middleweight champion Anderson Silva.
Then, in 2012, Jones beat Belfort by fourth-round submission.
Belfort, 37, also saw his prior testosterone replacement therapy request denied when the Nevada State Athletic Commission banned the practice last year.
The stacked card was announced hours after UFC Chairman Lorenzo Fertitta and President Dana White appeared Wednesday at a Las Vegas news conference to present a plan for stiffer drug testing and tougher penalties against those who test positive.
Jones submitted a positive test for cocaine Dec. 4, but was allowed to fight Jan. 3, defeating Daniel Cormier by unanimous decision, and was penalized with a $25,000 code-of-conduct fine by the UFC.
The UFC leaned on language crafted by the
Silva tested positive for two steroids in a pre-fight random test performed 22 days before his bout, but the Nevada commission failed to put a rush order on the test and it was returned after Silva beat Nick Diaz by unanimous decision on Jan. 31.
Silva also tested positive for a steroid in his post-fight test and Diaz was positive for marijuana.
The Wednesday news conference included a remark by UFC executive Lawrence Epstein that the company is not in the drug-testing business, but in the fight-making business.
White made that clear, dropping in during the session that new welterweight champion Robbie Lawler will make his first defense July 11 in Las Vegas against Canada's Rory MacDonald.
The May 23 card will also feature popular third-ranked lightweight Donald "Cowboy" Cerrone (27-6) fighting for the third time in 2015 against Khabib Nurmagomedov (22-0), the No. 2 lightweight.