Anthony Joshua lost three of his four title belts on Saturday night after a shock defeat to Andy Ruiz Jr.
Joshua was knocked down four times in seven rounds before the referee stopped the fight.
Since Saturday’s fight, a number of conspiracy theories have circulated.
Now, it’s been claimed that American boxer Joey Dawejko injured Joshua in sparring before his world-title fight against Ruiz.
Dawejko was drafted in for a late training camp with Joshua, according to World Boxing News.
The US fighter has lost his last three profession bouts, and has a similar build to AJ’s Mexican opponent.
On paper, he would be the ideal sparring partner ahead of the fight, which took place at Madison Square Garden, New York.
But, it has been claimed the Brit was hurt by Dawejko at the training camp, and the injuries were visible at media gathering ahead of the fight.
Dawejko has now reportedly been sworn to secrecy, and has supposedly been given a Matchroom card fight against Murat Gassiev.
Joshua’s promoter Eddie Hearn has constantly rejected claims of any conspiracy after the fight.
“This week has been incredible; the feedback, the conspiracy theories, what happened; he had a panic attack, he was hurt in sparring, all of which are absolute rubbish,” he said.
“AJ had a great camp. He spent the last part in Miami then he came to New York and, if anything, he wasn’t panicked enough. I don’t feel enough people are giving credit to Andy Ruiz.
“He was phenomenal on the night and he’s a fully deserved world champion now.
“Everyone’s searching for answers but the answer is AJ got caught by a shot in the third round that he never recovered from.
“Rather than looking for excuses – which to be honest there are none – just give the respect to Andy Ruiz.”
Hearn has this week confirmed that there would be a rematch between Joshua and Ruiz at some point in November or December.