Doubts have been cast on how many players will be involved with Ashleigh Barty, WTA World No.1 withdrew in the highest profile one so far.

For Ostapenko, she admitted that it is 'too dangerous' and that playing in America is not in her plans as a result with other tournaments taking precedent.

"I like to spend time at home, live a normal life," she told the Latvian press at the recent Merko Cup. "There are different rules in different countries. In Europe, the rules have been stricter, but the US girls have been training all the time.

If it is not canceled, the first tournament will be in Palermo. Then, my plans are to participate in Prague. America is not in my plans yet [this year] because driving there is too dangerous. "

While for Chinese Number 1, Wang; it is to do with travel restrictions and safety concerns which are among the highest on the list for players choosing to not be involved.

“I’m very sad that I have to make this announcement,” said Wang. “Due to travel restrictions and safety concerns, my team and I have to withdraw from Western & Southern Open and US Open. It is a tough decision for me.

I want to thank everyone for the extraordinary effort and hope to see you all next year in the US”.