- US player declines to expand on reasoning for not going
- Nadal, Thiem already have said they will not be playing
Serena Williams is the latest big-name tennis player to announce she will not be travelling to Tokyo for the Olympics.
The 39-year-old, who has four gold medals and made her debut at the Sydney Games in 2000, had previously said she was reluctant to go because she would not be able to take three-year-old daughter Olympia with her.
