The Ukrainian fighter has previously suggested that he could drop back down to cruiserweight after conquering the heavyweight division but the promoter believes that the world champion is too bulky in size to do so.

Warren told Sky Sports: "He won't. See the size of him, it's impossible.

"You've only got to look at the size of him, that's not going to happen."

Warren pointed out that a heavyweight world title bout against the winner of next month's clash between Daniel Dubois and Joseph Parker is the best option for Usyk.

He said: "(The most lucrative fight) for him [is] the winner of this. A big fight, a massive fight."

Warren believes that Dubois will have enough to maintain his IBF world title against Parker in February but is not expecting an easy night's work for his charge against the experienced New Zealander.

The promoter said: "I'll be confident after the fight. I believe in him, that's why we made the fight, but anything can happen with these big guys. They're big lumps. They throw bombs, the pair of them.

"It's not like Parker's a novice. He's been there, done it, been a world champion. He's on a roll at the moment. You see he's got a fighter's heart in that fight with [Zhilei] Zhang. He was on the floor twice that fight, still gritted his teeth and came through."

Warren is pleased to see how Dubois has developed into a feared world champion after his dominant victory over Anthony Joshua last year.

He said: "90 per cent of it is mental. It's took time. He's had a couple of hiccups on the way but you look at the fights he's had and what he's done - he's learned.

"He's a very young guy. He's matured mentally, which is really important. He's got the skills. He's comfortable with [trainer] Don Charles, who's done a brilliant job with him and this is his time."