Jason Day is not going to the Olympics because of the Zika virus, costing golf its No. 1 player as it returns from a century-long absence at the games.
The sport has lost two of its biggest stars in the last week.
Rory McIlroy, a four-time major champion, also said Zika will keep him from competing in Rio de Janeiro.
Day says his only reason for not going is concern over transmission of the mosquito-borne virus that has been linked to severe birth defects.
The 28-year-old Australian says while the risk is slight, it’s not one he is willing to take because he plans to have more children.
Day is the fifth golfer to specifically cite Zika for not going to Rio.
Four other golfers have turned down their chance to play.