It was confirmed on Wednesday the 2020 US Open will start behind closed doors on 31 August but there is still no guarantee the best players in the world will be there. While the six-time champion Serena Williams confirmed her participation at Flushing Meadows, some of the most senior players on both tours – Novak Djokovic, Rafael Nadal, Ashleigh Barty and Simona Halep – have expressed serious reservations about travelling to New York while Covid-19 lingers, and Roger Federer, who is 39 in August, has already retired for the season to recover from knee surgery. 2019 Wimbledon champion Halep has become the first top player to tentatively rule herself out of participation since the US Open’s announcement. “Given the conditions outlined in the US Open announcement this morning, as of today I do not currently plan to play in NYC,” she said in a statement. “However, as we know, this situation is fluid and that the conditions may change and improve before the entry deadline in mid July. I would like to underline that my decision is not set in stone.” The United States Tennis Association chief executive, Stacey Allaster, said there had been “significant discussions” with reluctant players before allowing them to bring up to three assistants with them, having earlier insisted on only one. “If the tournament was next week, I’m not going to speculate [how many would attend]. I am confident a lot of athletes want to play.” She added: “Each athlete will have two hotel rooms, one paid for, and they will be able to have three additional guests of their choice. We understand the needs of the athletes; we just need to recognise social distancing.” The tournament received a boost when Williams declared via video link: “I can’t wait to return to New York. It’s over six months since a lot of us have played professional tennis. I will miss the crowd, but I’m excited.” Williams, 39 in September, is running out of chances to equal Margaret Court’s all-time record 24 slam titles, and would relish the chance to do so at her home championships. Andy Murray is also keen to play at Flushing Meadows, where he won the first of his three majors eight years ago. Players will be tested for coronavirus on arrival and once a week after that: a maximum of three tests for the main tournament, four including the rescheduled Cincinnati Open, which will be held on site. The ATP also announced the rearranged French Open will start on 27 September, preceded by a revised schedule that begins with a 500 tournament in Washington on 14 August, before the Cincinnati Open at Flushing (21 August), a 250 event in Kitzbuhel (8 September), Madrid Masters (13 September) and Rome Open (20 September). The WTA’s updated calendar covers the remainder of the 2020 season and it will resume on 3 August at the Palermo Ladies Open in Italy. Its lucrative eight week autumn Asian swing remains, including the China Open in Beijing (12 October) and the Dongfeng Motor Wuhan Open (19 October), the biggest annual sporting event in the Chinese city where the coronavirus pandemic began. While both ATP and WTA events will resume with either reduced attendance or no fans, the Roland Garros organisers have ruled out holding the event behind closed doors.