RIO 2016: The real reason golf's male stars are withdrawing

The head of the Rio de Janeiro Olympics says the world's top four male golfers have withdrawn from the games because there is no money to be won - not because of the Zika virus.

"They tried to blame Zika, but the media have shown that they are not coming because there's no prize money," Rio organising committee President Carlos Nuzman said, speaking with the games set to open in just under three weeks.

Jordan Spieth withdrew this week from the Olympics, citing Zika.

He joined Jason Day, Dustin Johnson, and Rory McIlroy in also saying Zika was the main reason for skipping the first Olympic golf tournament in 112 years.

Their absence could be a setback for golf's future in the Olympics.

IOC President Thomas Bach has said that golf's future may rest on its ability to get top players to show up.

Golf is guaranteed a spot in the Tokyo Olympics in 2020, but could be in peril after that.