Anthony Joshua's rematch against Oleksandr Usyk is likely to be held on 20 August in the Middle East.
Ukrainian Usyk beat Joshua on points last year to claim the WBO, IBF and WBA (Super) titles.
A date of 23 July was pencilled in for the rematch but Usyk's promoter Oleksandr Krasyuk said they have been told to prepare for the later date.
Saudi Arabia is expected to host the rematch despite concerns about the country's human rights record.
Joshua, 32, has fought in Saudi Arabia once before when he beat Andy Ruiz Jr in their rematch in 2019.
It is the second time the highly anticipated rematch between Usyk and Joshua has been delayed.
After Usyk dominated the first encounter against the Briton at Tottenham Hotspur Stadium last September, Joshua immediately activated his rematch clause and had hoped to fight again in May.
But Russia's invasion of Ukraine and Usyk's decision to remain at home to help the war effort forced organisers to delay the bout.
Usyk, 35, left Ukraine in March to begin training while Joshua has spent his time away from the ring attempting to reorganise his coaching set-up as he looks to regain the belts.
American coach Robert Garcia has been hired with Joshua expected to adopt a more aggressive approach for the rematch.