Olympic gold medalist David Rudisha has pulled out of world championships because of a knee injury.
Olympic champion David Rudisha pulled out of the 800 meters at next month's world championships with a knee injury on Tuesday, robbing the track meet of another star attraction after U.S. sprinter Tyson Gay withdrew following a failed doping test.
"My knee problem is progressing well but unfortunately not fast enough to enable me to recover in time," Rudisha said in a statement through Athletics Kenya.
Rudisha's coach, Colm O'Connell, earlier told The Associated Press that the world record-holder had been sidelined from training for six weeks with the right knee problem and received treatment in Germany, but he wouldn't be ready to defend his title at the worlds.
"Finally we have made the decision," O'Connell said in a phone interview. "We held back for (a) long (time) hoping for improvement and he has improved quite a lot but we didn't want to do a crash course between now and the world championships, which may aggravate the injury since he has been out of training."
O'Connell said the 24-year-old Kenyan, who produced one of the Olympics' lasting performances in London last year to win 800 gold in a world-record time, first felt pain in his knee at the Adidas Grand Prix in New York in May. That led to him withdrawing from the Diamond League meet in Eugene, Oregon.
O'Connell said the injury may have occurred a few weeks before New York when Rudisha was running on rough ground in Kenya, where he trains in the high-altitude regions of Eldoret and Iten, but they couldn't be sure. Rudisha sought treatment in Germany and was initially hoping to recover in time for the Aug. 10-18 worlds.
"Doctors there (in Germany) said it may take three weeks for him to recover and we thought he would have seven weeks of training," O'Connell said. "But it has been longer. That's why we have decided to make the announcement."
The world's dominant two-lap runner, Rudisha was one of the athletes the IAAF would have desperately wanted to be at the worlds after Gay, the former 100 and 200 world champion, said this weekend he would not compete in the Russian capital after he was one of a number of top competitors to test positive for a banned substance.
Jamaican sprinters Asafa Powell -- the former 100 world record-holder -- and Sherone Simpson -- a three-time Olympic medalist -- also have failed drug tests, it emerged, just three weeks before the worlds. They were two of five athletes to fail doping tests at the Jamaican championships.