Heavyweight Daniel Dubois’ world title defence against Joseph Parker on Saturday is in doubt after the champion fell ill.

The Briton is under medical evaluation in Riyadh and did not attend Thursday’s news conference in Riyadh, Saudi Arabia.

“Unfortunately at this moment in time Daniel is being evaluated with the doctor,” his promoter Frank Warren said.

“When we have more news, we will share it with you and update you.”

A replacement is reportedly being sourced should the 27-year-old not be deemed fit to fight, with New Zealand’s Parker, 33, to remain on the card.

“If he is ill, I hope he gets better soon and I’m looking forward to Saturday and having a great show,” Parker said.

“I am ready to go. I’ve put in all the hard work with my team in Ireland my team here in Riyadh.”

Parker did attend the news conference alongside his manager, Spencer Brown, who said his team are in “lots of discussions.”

Brown added: “Joe will be there on Saturday whatever happens and he’s ready to win. Joe doesn’t care who he fights.”

Dubois has won 22 pro fights with two defeats. He won the ‘interim’ IBF title against Filip Hrgovic and was elevated to world champion when Oleksandr Usyk vacated the belt.

The Londoner made a first defence of his belt by stopping Anthony Joshua in five rounds at Wembley Stadium in September.

New Zealand’s Parker, 33, has a record of 35 wins and three defeats. He held the WBO heavyweight title between 2015 and 2017.

The contest is the chief support to the undisputed light-heavyweight fight between champion Artur Beterbiev and Dmitry Bivol.

Also on the card, Briton Hamzah Sheeraz challenges Carlos Adames for the WBC middleweight title.