Tennis’ 21-time Grand Slam winner, Novak Djokovic, says he's "preparing" as if he’ll be allowed to compete in August’s U.S. Open in New York.

Djokovic, who is coming off his seventh Wimbledon title, is not permitted to enter the United States due to his COVID-19 vaccination status. The U.S. requires non-U.S. citizens to show proof of being fully vaccinated before boarding a flight into the county, with limited exceptions.

On Saturday, Djokovic posted a message to his fans on social media, saying he is waiting to hear if he'll be able to enter the United States for the U.S. Open.