Italy's 100 metres Olympic champion Lamont Marcell Jacobs has withdrawn from Saturday's Diamond League meeting in Eugene after straining an unspecified muscle, the Italian Athletics Federation said.
The 27-year-old -- who pulled off a stunning upset in last year's 100m final in Tokyo -- will need "10 days rest", the federation added.
Jacobs strained the muscle when he won in Savona, Italy last week, his first 100m since winning in Tokyo.
He had a small problem with his glute muscles after the Savona race and said he had "felt held back somehow".
Jacobs would have faced a stellar field in Eugene, where the world championships take place in July.
Among those set to line up are the runner-up from the Tokyo final, Fred Kerley, and Canada's Andre De Grasse, who finished third before going on to be crowned the 200m champion.
Jacobs also pulled out on the day of the Nairobi meeting earlier this month due to intestinal problems.
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