To many, the Olympics represents the pinnacle of sport and a once-in-a-lifetime opportunity. But to others, particularly professional athletes, it’s simply not a priority.

Here are some sport stars you won’t be seeing in Brazil in August, by their own choice.

JOHN ISNER (Tennis)

Tennis: Citi Open-Isner v Johnson

American world No.18 John Isner, the United States’ top-ranked player, announced last week he wouldn’t be available for the Olympic campaign.

Isner instead has his heart set on playing the ATP event Atlanta, where he is going for a record fourth title.

“It’s a decision I didn’t take lightly,” said Isner, who lost to silver medallist Roger Federer in the 2012 London Olympics quarter-finals.

“Logistically, it would be pretty much impossible for me to do both.”

Isner’s decision was also reportedly influenced by the fact the Games competition does not offer rankings points.