Isaac Makwala has denied suffering from food poisoning after he was prevented from running in the men's 400-metre final at the IAAF World Championships in London on Tuesday.
The 30-year-old from Botswana was pulled from the 200m heats amid an outbreak of gastroenteritis at a team hotel on Monday and then denied entry to London Stadium for the 400m final a day later.
The IAAF cited a 48-hour quarantine procedure recommended by Public Health England as the reason for the exclusion.
But Makwala has insisted he should have been allowed to compete.
"They said I had food poisoning - which I don't have," he told ITV.
"I was not tested for that.
"They didn't even want to listen to me. They said 'no, you can't run because you are sick.'
"Sometimes I think maybe this is sabotage."
Simon O'Brien of the Botswana medical team was quoted by the BBC as saying: "He [Makwala] has got normal heart rate, normal body temperature.
"I believe there has been a slight confusion.
"No testing has been done. We sent messages to the IAAF saying we want our athlete to compete."
The IAAF said in a statement: "The IAAF is very sorry that the hard work and talent of Isaac Makwala won't be on display tonight but we have to think of the welfare of all athletes."