Deontay Wilder has made "the worst mistake of his career" by splitting from co-trainer Mark Breland who threw in the towel in his defeat to Tyson Fury, says Dillian Whyte.
The American heavyweight is no longer working with Breland, a long-term member of his coaching line-up, as he prepares for an expected third fight with Fury, with a date and venue still to be confirmed.
Breland, a former world champion himself, signalled the end of a stoppage loss to Fury in their WBC title fight in February, much to the dismay of Wilder, who is expected to keep faith with fellow co-trainer Jay Deas.
He's someone that cares about the athlete and the boxing side of things.
Asked about Wilder's decision, Whyte told Sky Sports: "I think it's the worst mistake he's ever made, because Mark Breland is the only person in his team that actually was a boxer and actually was a world champion. He was the only person that didn't care about money or fame.
"Someone who was actually from an emotional point, someone who understands, thinking about his health and did the right thing by throwing the towel in, because he could have got seriously hurt.
"He was getting hit with punches that weren't knocking him out, they were concussing him. Mark Breland knows what it's like, because Mark Breland has been in the same position Wilder was in. He's someone that cares about the athlete and the boxing side of things.
"Not just 'Bomb Squad', nonsense. He doesn't care about that. He's the only one in the team, you don't see him running around and shouting and screaming. He's just a little quiet guy, does his job.
"Deontay Wilder is an idiot, he clearly can't see it. Good luck to him, it's his team, he can do whatever he wants. But I think it's a bad mistake. Mark Breland is the only one that knows boxing in his team."
Whyte announced an amicable split from coach Mark Tibbs in July and has no intention of making any other changes to his team, including new trainer Xavier Miller, after his defeat to Alexander Povetkin in August.
"I don't look for excuses," said Whyte, who is preparing for a rematch with Povetkin on November 21, live on Sky Sports Box Office.
"Listen, my coaching team did what they were supposed to do. They got me to the fight injury free, they got me to the fight in shape. We were boxing well, we were winning rounds, we were fighting one of the best [opponents] I have fought in a long time.
"Early doors I was making him miss. The punches that he usually lands, I was making him miss, but that's the way it goes sometimes. It's boxing, you can win 11-and-a-half rounds and get stopped in the last 10 seconds.
"The team has done a great job, they got me in a good place. From what they got me from to what I was in Saudi. They got me down to 17 stone plus, we were happy.
"Credit due to Povetkin, fair play to him, he threw a good punch and it landed and what more can I say. Now we go into camp, we put it right, we come back again. I believe I beat Povetkin nine times out of 10."