In addition to Del Potro and Osaka, 10 former singles champions at the event are scheduled to play this year. They are five-time winner Roger Federer — runnerup last year — Novak Djokovic and Rafael Nadal on the men’s side, and Simona Halep, Serena Williams, Maria Sharapova, Victoria Azarenka and Caroline Wozniacki on the women’s side.
Source: latimes.com – Los Angeles Times