Ferdinand Omanyala, who holds the African 100m record, is injured and has pulled out of this week's Diamond League final in Zurich, the last event before the Tokyo world championships.
The 29-year-old is one of 17 Kenyans to have qualified for Zurich where the globe's top athletes will be compete on Wednesday and Thursday.
"I regret to inform you that I will be unable to participate in the Diamond League final," Omanyala said on Monday, citing recent deep muscle, and hip and glute pain.
"I am optimistic about my recovery and anticipate being fully fit for Tokyo (September 13 to 21)," he said in a statement posted on Instagram.
Omanyala, who set the African 100m male record of 9:77 in September 2021, was selected at the Kenyan trials in July as the country's only male entrant in the 100m at Tokyo.
He has struggled to find his winning form in the Diamond League this season.
He finished second in China and Morocco, but trailed in last in Shanghai, in a race won by South Africa's Akani Simbine with Jamaica's Olympic champion Kishane Thompson in second.
Faith Kipyegon, the three-time world 1500m champion, and 10000m champion Beatrice Chebet will be competing in Zurich.
They join the Olympic 800m champion and Diamond League winner Emmanuel Wanyonyi, who has chalked up four wins with the fastest times this season.