Conor McGregor will no longer fight Michael Chandler at UFC 303 on June 29 in Las Vegas, UFC president Dana White said Thursday night.

McGregor (22-6) was scheduled to headline the event but has withdrawn because of injury. It's the first time in McGregor's storied UFC career he's pulled out of a fight for any reason.

The new main event is a light heavyweight title fight between Alex Pereira and Jiří Procházka, according to White.

White also announced two more new fights to the card: Diego Lopes will face Brian Ortega in the co-main event and Carlos Ulberg will now fight Anthony Smith in a light heavyweight bout after Jamahal Hill, who was slated to fight in the co-main event, is out due to injury.

According to White, the sellout event was on pace to set a record for the UFC, with a live gate of more than $20 million. The UFC has not announced whether the nontitle welterweight bout between McGregor and Chandler will be rescheduled.

McGregor, 35, was set to return to competition for the first time since he suffered a broken leg in a TKO loss to Dustin Poirier in July 2021. The former featherweight and lightweight champion has only fought four times since a blockbuster boxing match against Floyd Mayweather Jr. in 2017.

McGregor is 1-3 in those appearances, with two losses to Poirier and a submission defeat to Khabib Nurmagomedov in a 2018 title fight.

The June fight being called off is a disappointing chapter in what's become something of a saga between McGregor and Chandler. Chandler, a former champion in Bellator MMA, first called out McGregor in earnest in 2022. The UFC announced the two would coach against each other on "The Ultimate Fighter" reality series in early 2023, which went ahead as scheduled that spring. A fight date did not come together until early this year, however, for various reasons.

The UFC's former drug testing partner, the United States Anti-Doping Agency (USADA), claimed McGregor's situation led to the dissolution of its UFC program, as the promotion wanted to grant McGregor an exemption of a six-month testing requirement following his leg injury. UFC chief business officer Hunter Campbell denied that assertion and demanded a public apology.

The UFC has since partnered with several other agencies to run its drug program.

McGregor, of Ireland, promised via a tweet that his return to the Octagon this year would be the start of the "Greatest Comeback in Sports History." The UFC scheduled a public news conference with McGregor and Chandler on June 3 at 3Arena in Dublin, but canceled the event just 12 hours before doors were to open, which prompted speculation on the status of the fight.

Chandler, 38, has not fought since a back-and-forth loss to Poirier at UFC 281 in November 2022. He has only expressed a passing interest in potential bouts against Nate Diaz, who is currently not signed to the UFC, or BMF titleholder Max Holloway.