Anthony Taylor, who faced Tommy Fury back in August, believes the light heavyweight prospect would have been overwhelmed by Jake Paul.
Fury secured a lackluster four round decision win over Taylor. On the same card, which took place in Cleveland, Paul appeared in the main event and won an eight round split decision over former UFC champion Tyron Woodley.
Paul and Fury were scheduled to collide in the main event of a Showtime Pay-Per-View this coming Saturday night in Tampa, Florida.
Less than two weeks ago, Fury withdrew with a broken rib and a chest infection.
He was quickly replaced by Woodley, who gets the opportunity to avenge his August loss.
Taylor, who worked in the past as a sparring partner for Paul, believes his friend would have boxed Fury's ears off.
"[Fury is] a novice. He just had height on me. He doesn't have knockout power. If Jake fought Tommy, it would have been the same fight as Anthony Joshua vs Oleksandr Usyk. Usyk moves like Jake moves. Jake, against Tyron Woodley, touched every corner and crevice of that ring. Jake has better cardio than Tommy. His IQ and his awareness are better," Taylor told Sky Sports.
"The real reason [Fury withdrew] is that his conditioning was not on point. I fought Tommy - his cardio was bare, even in important rounds. He had six weeks to get into shape but it takes longer than that. Big John Fury knew that and, I guarantee, he pulled the trigger on this fight because he didn't trust Tommy's cardio.
"Tommy has no shame. He is not a prideful man. He's not Tyson Fury. Tommy is a good kid, young and upcoming, maybe a world champion in seven years' time. But now? He's in over his head. His dad and Tyson are talking him up. He is a level behind Jake in terms of his trash talk and his boxing."