Montreal - Wimbledon runner-up Milos Raonic said on Friday he was withdrawing from the Olympics because of fears over the Zika virus, dealing another blow to the tennis tournament in Rio.
The world number seven from Canada, who was defeated by Andy Murray in Sunday's Wimbledon final, said he had taken the decision "with a heavy heart".
"It is with a heavy heart that I am announcing my withdrawal from participation in the Rio 2016 Olympic Games," the 25-year-old announced on his Facebook page.
"After much deliberation with my family and coaches, I am making this decision for a variety of health concerns including the uncertainty around the Zika virus.
"This was a difficult, personal choice and I do not wish for it to impact the decision of any other athlete heading to the Games."
John Isner of the United States, Austria's Dominic Thiem, Australian duo Bernard Tomic and Nick Kyrgios as well as Spanish veteran Feliciano Lopez have all opted, for various reasons, not to take part in the Olympics.
Italy's former French Open champion Francesca Schiavone has also turned down the opportunity to play in Rio while former world number ones Maria Sharapova and Victoria Azarenka will also be missing.
Sharapova is serving a doping suspension while Azarenka announced on Friday that she is pregnant and won't compete again in 2016.
Eccentric Latvian player Ernests Gulbis described the Rio event as "tennis tourism" as the Olympics do not offer either prize money or ranking points.
Tennis Canada said it respected Raonic's decision and that it will seek to nominate 43-year-old Daniel Nestor to partner Vasek Pospisil in the men's doubles.
"We fully respect Milos' decision as we are sure this is not one he made easily," said Kelly Murumets, the president of Tennis Canada.
"Milos represents Canada proudly week after week around the world and we look forward to future opportunities for him to join Team Canada again on the court."
Fears over Zika have already seen the image of the golf event in Rio badly tarnished with the sport's top four players - Jason Day, Jordan Spieth, Rory McIlroy and Dustin Johnson - all choosing not to play.
Earlier on Friday, Spanish superstar Rafael Nadal was included on the entry list for the Olympics after appealing to the International Tennis Federation (ITF).
The 14-time Grand Slam champion had not met the qualifying criteria, which involves a set number of Davis Cup appearances in an Olympic cycle, for next month's Games.
World number four Nadal hasn't played since a wrist injury forced him to withdraw from the French Open and also ruled him out of Wimbledon.
Nadal was the gold medallist at the 2008 Beijing Olympics but missed the 2012 London Games because of a knee injury.
He is due to carry Spain's flag at the opening ceremony in Rio on August 5.
Reigning champions Andy Murray and Serena Williams will defend their Olympic titles on the Rio hard courts, the ITF had already confirmed.
Top stars including world number one Novak Djokovic and Roger Federer are also playing in Brazil.