Kotut sustained a slight injury in training and is not back to full fitness.
2022 Hamburg Marathon champion CyBrian Kimugor Kotut has withdrawn from the Tokyo Marathon scheduled for Sunday 5 March.
The 31-year-old long-distance runner, who trains in Kapsabet, Nandi County, has withdrawn due to an injury.
Kotut was ready to take on 2021 London Marathon champion Sisay Lemma of Ethiopia, who was lining up as the fastest in the field with a personal best time of 2:03:36.
"I was on course with my training, but I picked up an injury which came with a lot of pain, forcing me to withdraw from the Sunday race," Kotut told reporters on Friday.
Kotut, the younger brother of three-time London Marathon winner Martin Lel, holds a personal best time of 2:04:47 across the distance.
Apart from Kotut, Joan Chelimo has also been forced to pull out of the race due to injury, while Evans Yego declined the organizers' invitation.
Their withdrawal has now handed Milano Marathon champion Titus Kipruto and 2022 Berlin Marathon second-place finisher Rosemary Wanjiru another opportunity for a shot at the world marathon titles.
Kipruto will team up with Bernard Koech in the men's marathon, where they will be seeking to claim the title Eliud Kipchoge won in the 2022 edition.
Wanjiru, on her side, will wrestle for the title with the Ethiopian duo of 2019 Berlin Marathon champion Ashete Bekere and Tigist Abayechew.