Switzerland’s world number four Stan Wawrinka has withdrawn from the Olympic Games because of a back injury.
Wawrinka, 31, aggravated the injury in the Rogers Cup in Canada, meaning five of the men’s top-10 players will not participate in Rio.
Roger Federer, Tomas Berdych, Milos Raonic and Dominic Thiem have also withdrawn.
“I would like to have witnessed my third Olympic Games,” Wawrinka said. “This will not be possible now.”
The injury is another blow for the Swiss team after 34-year-old Federer, the world number three and 2012 silver medallist, withdrew with a knee injury.
That leaves just two remaining players – Martina Hingis, whose last appearance at the Games was in 1996, and Timea Bacsinszky – from the initial six-member Olympic team.
World number seven Milos Raonic and world number eight Tomas Berdych cited the Zika virus for their omission.
Tennis is not the only sport to suffer large withdrawals, with more than 20 male golf players pulling out of Rio 2016.
