Saturday's world title fight between Daniel Dubois and Joseph Parker is in doubt amid illness concerns for the British heavyweight in Saudi Arabia.
A replacement fighter is being considered with Dubois being evaluated by a doctor, as first reported by The Ring Magazine - owned by head of Riyadh Season, Turki Alalshikh.
Dubois will miss Thursday evening's press conference, which is being streamed live on the Sky Sports app from 6pm.
Lawrence Okolie, David Adeleye and Mourad Aliev are among the options being considered to potentially replace Dubois and fight Parker on Saturday night, a source has advised The Ring.
Sky Sports Boxing's Johnny Nelson said shortly before Thursday's press conference: "A friend of mine was speaking to Don Charles this morning and he was in high spirits, he was asked if he was coming to the press conference and he said: 'No I will let Daniel do the talking.' So, this is fresh news.
- Dubois vs Parker and Beterbiev vs Bivol 2: Book to watch on your TV
- Dubois vs Parker: Watch the fight online
- Dubois vs Parker and Beterbiev vs Bivol 2: All the ways to book
"Unless it's a red herring. But what if he doesn't fight, what do we do? It's not the top of the bill, it's still a great fight.
"Will they be able to get someone in to stand in for short notice for Joseph Parker? At this late stage I will be very surprised but if they do, depending on how long they knew about this, they could get someone like Martin Bakole, it makes the fight exciting but it's just pure speculation."
Sky Sports Boxing's Andy Scott added: "This fight isn't off yet but we do know that a doctor is on his way, if he's not already there.
"Frank Warren is down in a huddle below me. He said they will await the evaluation from the doctor Daniel Dubois will not be travelling to the press conference tonight.
"So we will not see Daniel Dubois.
"I can't quite believe we're in this situation. What do you do? People get sick all the time. We shouldn't speculate and we should wait to see what the doctor says."
Daniel Dubois vs Joseph Parker and the Artur Beterbiev vs Dmitry Bivol rematch will be live on Saturday February 22 on Sky Sports Box Office. Book now!