World record-holder Patrick Makau of Kenya has pulled out of this month's Berlin marathon due to a knee injury, his agent said in a statement on Friday.
"I wanted to compete and I remained highly focused and positive, but after discussing my options with my management team, I've realised that I can't race unless I am healthy and prepared to perform at my very best," Makau said.
"I trust the doctor and I need to focus on recovering from this problem."
Makau, 28, had been planning to attempt to beat the world record of two hours three minutes and 38 seconds which he set in Berlin two years ago.
"I do believe that Patrick's objective at this stage of his career is not just to protect his world record, but to attack it," his agent Zane Branson said.
"Sadly, this now might have to wait until next year."