Conor McGregor has been sidelined from UFC 303 due to an injury, UFC CEO Dana White announced Thursday.

This development also removes his welterweight opponent, Michael Chandler, from the June 29 event in Las Vegas.

It is unclear when or if the non-title bout between McGregor (22-6) and Chandler (23-8) will occur. The nature of McGregor's injury has not been made public.

The new UFC 303 headline fight will be the light heavyweight title clash between Jiri Prochazka and champion Alex Pereira.

In another schedule change, former UFC light heavyweight champion Jamahal Hill is out of his slated fight against Carlos Ulberg. Instead, Anthony Smith will oppose Ulberg. Hill's original opponent was due to be Khalil Rountree Jr., but the latter is serving a two-month doping ban.

Added to the card as a new co-main event will be a matchup of featherweights Diego Lopes and Brian Ortega.

McGregor, 35, was preparing for his first fight since July 2021, when he lost for his second straight matchup with Dustin Poirier. McGregor last won when he beat Donald Cerrone in January 2020, following a defeat to Khabib Nurmagomedov in October 2018.

Chandler, a 38-year-old Missouri native who fights out of Florida, has also lost three of his past four bouts. His most recent action was a defeat against Poirier in November 2022.