World number two Nadal, who captured a fourth US Open and 19th major in New York last year, said he remained convinced the coronavirus pandemic still casts huge doubts over the tennis calendar which has been suspended since mid-March.
“We cannot resume until the situation is completely safe and fair in terms of health in that all players, wherever they come from, can travel and play tournaments in safe conditions,” Nadal told reporters in a video conference call.
“If you told me to play the US Open (scheduled to start on August 24) today, I would say no.
“In a few months, I don’t know. I hope so. We have to wait for people to return to normal life. And when it does, wait to see how the virus evolves.
“It’s very difficult for me to separate what the world is experiencing from my point of view on tennis, that’s why I was very pessimistic a few weeks ago.”
The ATP and WTA schedules have been on ice since March with action not set to resume until the end of July at the earliest.
Wimbledon was cancelled for the first time since the Second World War while the French Open has been shifted to September/October.
In normal times, the Roland Garros event would have been deep into its second week by now with Nadal expected to win the Paris trophy for the 13th time.
The US Open remains on the schedule but there are still doubts over whether or not it will take place with New York being the epicentre of the COVID-19 crisis in the United States.
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