Novak Djokovic is currently quarantined in Australia as he awaits a decision on the appeal of his visa cancellation. The Serbian tennis star is on the verge of getting booted from the country ahead of the Australian Open because of his COVID-19 vaccine status, putting his status for the Grand Slam event in serious jeopardy.

Djokovic announced earlier in the week that he had received a medical exemption from the vaccine in order to play in the Australian Open, which is set to begin on Jan. 17. However, upon arriving in the country, he “failed to provide appropriate evidence” to meet the country’s entry requirements, per Chantal Da Silva of NBC News. 

With Djokovic's Australian Open status in limbo, fellow tennis superstar Rafael Nadal has weighed in. While Nadal has some sympathy for Djokovic, he also noted that these vaccine rules have been in place for months and Djokovic knew the consequences.

Via Sky Sports:

“Of course I don't like the situation that is happening,” Nadal told reporters after winning his match at the Melbourne Summer Set ATP 250 tournament. “In some way I feel sorry for him.

“But at the same time, he knew the conditions since a lot of months ago, so he makes his own decision.”

Nadal tested positive for COVID-19 last month but is now gearing up for the Australian Open. The 35-year-old had more to say about the situation:

“[It] seems some rough situation,” Nadal said. “It's normal that the people here in Australia get very frustrated with the case because they have been going through a lot of very hard lockdowns, and a lot of people were not able to come back home.

“I believe in what the people who knows about medicine say, and if the people say that we need to get vaccinated, we need to get the vaccine. That's my point of view.”

Novak Djokovic has won the Australian Open a record nine times and three times in a row. Djokovic and Nadal are tied with Roger Federer with 20 major titles.