half of the ATP top 10 is not there: Switzerland's Roger Federer (out with injury for 6 months) and Stan Wawrinka, Canada's Milos Raonic, Czechia's Tomas Berdych and Dominc Thiem of Austria. Rafael Nadal is playing all three events in Rio, but he is coming off a wrist injury which caused him to withdraw from Roland Garros and skip Wimbledon.
World #1 Novak Djokovic and World #2 Andy Murray are in Rio with Nadal. Murray was selected to be hold his country's flag in the opening ceremony. He is the defending champion, having won the Gold Medal match against Roger Federer at the 2012 London Olympics. Juan Martin del Potro won Bronze by defeating Djokovic, whom he faces in the first round here. Nadal is in Djokovic's half of the draw.
On the women's side, the draw has placed Venus and Serena in the top half together. The potential quarterfinals are: Serena versus Petra Kvitova (or Caroline Wozniacki), Garbine Muguruza versus Venus, Madison Keys versus Radwanska and Angelique Kerber versus Johanna Konta (or Sveta Kuznetsova).