The freshly-crowned 100m world record holder Tim Montgomery has pulled out of this weekend's athletics World Cup in Madrid.
The American's manager, Charles Wells, said: "He's not physically ready to run. His body is hurting. It's impossible for him to come back. It takes two weeks for his body to recover."
The 27-year-old Montgomery, who is already in Madrid to support his girlfriend Marion Jones and the rest of the American team, clocked 9.78sec in Paris on Saturday - shaving one hundredth of a second off Maurice Greene's record.
His efforts earned him Tuesday the new number one position in the 100m rankings which, with his new accolade as the fastest man on earth, is making sleep difficult to come by.
"I cannot really believe it. It's hard to explain what it feels like - I'm getting no sleep at night.
"I knew I was going to do it - I just didn't know when," said Montgomery.
There is still an outside chance that Montgomery could be called up to run in the 4x100m relay but that will only happen if the Americans suffer an injury crisis.
His absence from the 100m logically lets in Great Britain's Dwain Chambers to steal the show and have a tilt at the European record of 9.87 he holds jointly with Linford Christie which he set in Paris when running second to Montgomery.