Spanish tennis legend Rafael Nadal announced on Monday that he had tested positive for COVID-19 after arriving in Spain following a tournament in the United Arab Emirates. 

"Hi all. I wanted to announce that on my return home after playing the Abu Dhabi tournament, I tested positive for COVID," Nadal wrote on Twitter. "I am having some unpleasant moments but I hope that I will improve little by little. I am now homebound and have reported the result to those who have been in contact with me."

Nadal returned to professional competition for the first time in almost six months at the Mubadala World Tennis Championship in Abu Dhabi last week. He had been dealing with a foot injury and, as a result, skipped a series of major events this year including Wimbledon, the U.S. Open and the Tokyo Olympics. 

The latest news means it is unclear whether the former world number one will play in the Australian Open, beginning on January 17, 2022. Nadal had previously expressed doubt about participating but many expected him to compete at Melbourne Park.

"As a consequence of the situation, I have to have total flexibility with my calendar and I will analyze my options depending on my evolution. I will keep you informed of any decisions about my future tournaments. Thank you all in advance for your support and understanding," Nadal said on Monday. 

After getting knocked out by Novak Djokovic in the men's semifinals at the French Open in June, Nadal now shares the record of most Grand Slam titles (20) with Djokovic and Roger Federer. Federer went through multiple knee surgeries and made it very clear he is unlikely to return to tennis until mid-2022.

And there is no guarantee that Djokovic, the reigning champion of the Australian Open, will appear at Melbourne Park since he refuses to reveal whether he is vaccinated against the coronavirus, a requirement to take part. 

"I am not with or without, I am just following what the organization of health says. And I don't pretend to know more than what the authorized people say," Nadal said when asked about his views on the Australian Open's vaccination policy. "If the people who really know about it say that we need to be vaccinated, who I am to create a different opinion? That's all I can say."