Jamaican sprinter Asafa Powell has withdrawn from the London Grand Prix to make sure he is fit for the London Olympics.
Powell was due to take on American rival Tyson Gay over 100 meters on Friday, but he has a groin strain.
Powell says he has been "carrying some soreness in my groin since the Olympic trials and have been unable to train at 100 percent."
In a statement from London GP organizers, he added: "I need to ensure I'm ready for the games and cannot take any risks. I will be ready in August."
The Olympics start on July 27.
Powell also missed last year's London Diamond League meeting because of a groin injury, which led to skip the world championships in August.