Barty is yet to decide if she'll defend the French Open title she won last year for her breakthrough singles major. The clay-court Grand Slam event was postponed earlier in the year and rescheduled to start on September 27, after the US Open.
Australia's closed international borders would make it difficult for Barty to travel during the pandemic. Technically, Barty would have to receive permission from the government to travel abroad, and flight options are limited. On returning to Australia, travellers face a mandatory two weeks in quarantine.
Other players have expressed concern about travelling to the US, where more than 150,000 people have died from Covid-19.
Barty had to make her decision because entries were open for the Western & Southern Open, which is scheduled for August 20-28 and was moved to the same hard courts at the Billie Jean King National Tennis Centre slated to host the US Open.
Serena Williams, Coco Gauff, Novak Djokovic and Rafael Nadal were on yesterday's initial entry lists — but Barty, two-time Grand Slam champion Naomi Osaka and 2019 US Open champion Bianca Andreescu were not — for the tournament moved from Cincinnati to Flushing Meadows.
Being on yesterday's lists doesn't necessarily mean a player will compete at the tournament.
No sanctioned professional tennis events have been played since March because of the coronavirus.
The women's and men's tours plan to return in August. The women's tour still aims to return next week at Palermo, Italy.
- AP