By Brian Homewood
DOHA (Reuters) - Botswana's Nijel Amos, one of the favourites to win the 800 metres at the world championships, withdrew before his opening heat on Saturday with an Achilles problem.
The 25-year-old, silver medallist at the 2012 Olympics, was due to run in the second heat, in front of a sparse crowd at the Khalifa stadium, but did not start.
"Have dealt with my share of injuries in the past there was nothing to suggest anything wrong prior to departure," he said on Instagram.
"Inexplicably, upon arriving the Achilles on my left side was tight (nothing I have experienced previously) -- had plenty of time to rest and treat knowing I have trained well.
"It has not responded to anything so regrettably, I have to scratch out World Championship and get head onto (Tokyo)," he added referring to next year's Olympics
Amos won the Diamond League race in Monaco in 1:41.89, the fastest time since the London Olympics.
He pulled up during his next race in London and limped off the track but, two weeks later, was second at the Weltklasse meeting in Zurich suggesting the problem was not serious.
(Writing by Brian Homewood; Editing by Ken Ferris)