Athletics:Defending champion Tyson Gay has joined Britain's Dwain Chambers in ruling himself out of the 200m at the World Championships in Berlin.
The American chased home Usain Bolt in Sunday's extraordinary 100m final, taking silver in 9.71secs - the third fastest time in history behind the gold medal winner's 9.58.
But Gay has been carrying a niggling groin injury for some time and after consulting doctors yesterday he has been told to miss the 200m which gets under way later today.
It is a huge blow for the sprinter, who was also struggling with injury at last year's Olympics, in which he failed to win a medal.
"Rather than risk further injury, I've decided that I will not compete in tomorrow's (Tuesday) first round of the 200m," Gay said.
"I would like to be a part of Team USA's 4x100m and believe this decision will give me the best chance to be ready for the relay. I want to help our relay as best I can."
The US team will name its first-round relay line-up after the men's 200m final on Thursday. The first round of the relay is on Friday, with the final the following day.
Chambers had earlier pulled out due to a calf injury.
The British sprinter finished sixth in the final of the 100m, clocking a season's best of 10.00 seconds.
Bolt, the Olympic champion and world record holder at 200m, is the hot favourite to complete the sprint double once again.