Japan's Hideki Matsuyama has become the latest top-20 ranked golfer to withdraw from the Olympics because of concerns about the Zika virus.
The 24-year-old, ranked 17th in the world, said he often had strong reactions to insect bites.
"I cannot be 100% sure about my safety from the Zika virus," he said.
World number one Jason Day and Rory McIlroy also pulled out of Rio with concerns about Zika as golf returns to the Olympics after 112 years.
"Although I realise that my potential success would help grow the game in Japan, I have come to the conclusion that I cannot put myself or my team member's health at risk," Matsuyama added.
The Zika virus is mosquito-borne and has been linked to defects in newborn babies, prompting those looking to start a family to take extra precautions.
Olympic chiefs and the World Health Organisation have issued guidance for athletes and visitors to Rio and say the risk of catching Zika is low.