Mandatory challenger Kubrat Pulev could beat Anthony Joshua “very easily” if he fights again like "a novice", believes his promoter Kalle Sauerland.
Joshua is mandated to defend his IBF heavyweight title against No 1 contender Pulev but, after also winning the WBA 'super' belt against Wladimir Klitschko last week, his next opponent is unclear.
Pulev's promoter Sauerland confirmed that negotiations are taking place to challenge Joshua, who they believe showed a lack of experience despite beating Klitschko.
If the novice turns up, Pulev will take care of business very easily. If the Anthony Joshua turns up that exploded in round 11 and half of round five, then it's going to be a difficult night for anyone.
"We saw two Anthonys - I saw possibly one of the most sensational heavyweights I have seen in many years, and I also saw a novice at times," Sauerland exclusively told Sky Sports.
"If the novice turns up, Pulev will take care of business very easily. If the Anthony Joshua turns up that exploded in round 11 and half of round five, then it's going to be a difficult night for anyone. The exciting thing about Anthony Joshua is that he is learning, and Pulev is someone who has beaten very good guys throughout his career."
Sauerland confirmed that they rejected "a very good offer" for Pulev to fight Joshua last December because they anticipated a more lucrative opportunity this year. Retaining Pulev's mandatory status until the conclusion of a rematch between Joshua and Klitschko remains a possibility, Sauerland acknowledged.
He said: "It's a fight that we were offered before and turned down because we knew we were mandatory.
"It's key that we have that fight. It's a fight that [Pulev] has earned. There is a reason why there is a mandatory challenger in the sport - it's because he is the guy who has fought eliminators to get there.
"The [Joshua-Klitschko] rematch is obviously a great fight, we don't want to get in the way of great fights, so maybe there is a solution that can be found which secures our fight for a certain time of the year.
"We're not interested in interim titles. I'm not a fan of interim titles. There is a world champion or there is not a world champion."
Pulev's sole defeat came three years when he challenged then-world champion Klitschko, losing via fifth-round knockout, but Sauerland isn't disheartened by that result.
"Take a look at the fight and see how he catches Klitschko and Klitschko catches him on the counter," he said. "It was a case where I was off my seat, and I was very much totally on my seat afterwards."
Joshua's promoter Eddie Hearn told Sky Sports last week about their desire to avoid vacating the IBF belt that was won against Charles Martin last April.
Hearn said: "It is our intention to navigate AJ to become the undisputed champion and capture every belt in the division. We certainly do not want to vacate belts, but we also want to make the best and biggest fights out there."
Sauerland added: "I would be disappointed and I don't expect him to vacate. I would be very, very surprised if he didn't fight Pulev."
The IBF declined to comment.