Click through to see all the biggest athletes who'll be missing from the Rio Olympics, and their reasons why they won't be there.
2/16
Jason Day
World number one Day withdrew from the Olympic Games because of the Zika virus.
3/16
Sally Pearson
Was scheduled to be the Australian Olympics captain but a torn hamstring has forced her out of Rio.
4/16
Jarryd Hayne
Announced in a Facebook post that he had been cut by Fiji coach Ben Ryan from his Rio Olympics squad. Hayne is now likely to return to the NRL.
5/16
Nick Kyrgios
Kyrgios ruled himself out of competing at the Rio Olympics over his dispute with the team’s leader Kitty Chiller and the Australian Olympic Committee.
6/16
Marc Leishman
Leishman pulled out of the Rio Games because of concerns about the Zika virus.
7/16
Adam Scott
Scott has been critical of golf's re-inclusion in the Olympics, calling it an exhibition. He's been critical of the format that is based on individual play instead of team play. He also noted he wanted to spend more time with his family.
8/16
Michael Diamond
Diamond, a dual Olympic champion, lost his bid to compete at a seventh Games after he was charged with drink-driving and firearms offences and stripped of his gun licence last month.
9/16
Bernard Tomic
Tomic pulled out of the Rio Olympics because of his busy playing schedule and his own personal circumstances. “I make this decision based on what is best for my tennis career."
10/16
Rory McIlroy
McIlroy made himself unavailable for selection due to health fears over the Zika virus. The Northern Irishman is planning to start a family with his fiancee, Erica Stoll, and worried about the links between Zika has and defects among newborns.
11/16
Lebron James
James wanted to take some time off after being named the NBA finals MVP. The fact he already has two Olympics golds to his name also played a part in his decision.
12/16
Stephen Curry
Curry did not specifically cite Zika in his reasons for not attending Rio, but noted "other factors" played a role in his decision.
13/16
Anna Flanagan
Hockeyroos star Flanagan was snubbed for the Rio Olympics despite being cleared for selection after she failed to disclose a drink driving conviction.
14/16
John Isner
Isner, the top-ranked American male tennis player, said logistics and scheduling conflicts were the main contributors in his decision to skip the Rio Olympics.
15/16
Russia
68 clean athletes are arguing they should be allowed to compete after the International Association of Athletics Federation banned Russia's athletics federation from the Olympics.
16/16
Dustin Johnson
World No. 2-ranked golfer announced that he would also be withdrawing his name because of concerns over the Zika virus and his plans to have more children.
Yahoo Sport Australia
All the biggest athletes who've withdrawn from or been forced out of the Rio Olympics.