Asafa Powell has been ruled out of the 100 meters at the World Athletics Championships because of a groin injury, eliminating defending champion Usain Bolt's biggest rival from the marquee event.

Powell's manager Paul Doyle told The Associated Press on Thursday that the injury sustained several weeks ago was still giving the fastest man of the season too much trouble. He added that the Jamaican could be fit by the time of the 4x100 relay during the final weekend of the championships.

"The groin strain is still lingering," Doyle said. "He is not quite 100 percent."