Jamaica's Asafa Powell has been ruled out of the individual 100 metres at the World Championships in Daegu with a groin injury, but hopes to run in the relay, his agent Paul Doyle has told Press Association Sport.
The 28-year-old sprinter, fastest man in the world this year, had been expected to be one of the main challengers to defending champion and compatriot Usain Bolt at the event in South Korea.
But he will not line up when the heats get under way on Saturday due to the injury - the same problem which forced his withdrawal from the Aviva London Grand Prix at Crystal Palace earlier this month.
A statement from Doyle read: "Asafa Powell has officially withdrawn from the 100m event in Daegu citing a continued groin strain. Powell suffered a groin strain in Budapest on July 30 and has had recurring tightness and pain ever since.
"After Budapest, Asafa missed eight days of training before he could attempt to sprint again. When he returned to the track he was able to sprint but it caused the groin to flare up.
"He has received all sorts of treatments over the past two weeks in the hope of being prepared to run the 100m here in Daegu but today Asafa made the final decision not to run. He feels he would not be at 100% and may have trouble coming back after each round.
"Asafa is very disappointed to say the least. He was really hoping to be able to run in what was going to be one of the most anticipated races of the championships. He is still optimistic to be able to run the relay."
Amid confusing scenes at a Jamaican team press conference, it was fellow sprinter Michael Frater who appeared to let the cat out of the bag.
While most reporters waited to speak to Bolt, Frater answered a question about his prospects by saying: "I didn't come here expecting to run the 100m but unfortunately Asafa couldn't make it."
Jamaica team leader Grace Jackson then refused to answer definitely if Powell would compete, while Bolt also claimed to be in the dark when he eventually appeared on stage, adding: "Asafa's out? That's the first I heard of it."
Before pulling out of the meeting at Crystal Palace, Powell had spoken about his determination to claim a first global title.
The 28-year-old said: "I've learned not to get too comfortable, not to think that the medals are in the bag because I have a fast time. I have to work there and get it.
"I try now to think of big races as just another race. It's not easy because we are all human and it's hard at a world championship final."