Novak Djokovic and Serena Williams on US Open entry lists -- but that doesn't mean they'll play

By Amy Woodyatt, CNN

Updated 0859 GMT (1659 HKT) July 21, 2022

Novak Djokovic is unable to enter the US due to rules which require travelers to be fully vaccinated.

(CNN)Serena Williams is included on the entry list for this year's US Open, along with 21-time grand slam champion Novak Djokovic, who is currently unable to enter the country due to rules that require travelers to be fully vaccinated against Covid-19.

However, the inclusion doesn't mean that either will definitely play.Williams returned to grand slam action this month at Wimbledon after a year-long break — but was knocked out in the first round after a three-hour, 11-minute tussle with France's Harmony Tan.But Williams, who turned 40 last September, is refusing to give up on her pursuit of a record-equaling 24th grand slam title, five years after she claimed her last at the Australian Open. She is currently entered in tournaments that will take place later this summer in Toronto and Cincinnati.Williams, who turned 40 last year, is included in this year's US Open entry list.Meanwhile, more than 23,000 people have signed an online petition on change.org calling for the United States Tennis Association (USTA) and the US government to allow Djokovic to compete in the grand slam.Read MoreDjokovic's refusal to take the Covid-19 vaccine has hindered his participation in tournaments around the world, with the Serb unable to defend his Australian Open title in January after being deported following a period in detention.He later told the BBC that he would be willing to miss tournaments to maintain his unvaccinated status and he has forgone playing in several tournaments throughout the year, including those based in the US, such as the Miami Open and Indian