Novak Djokovic returned home yesterday after being thwarted from defending his Australian Open title only to face a new predicament: He could be barred from the French Open this year, too, if he's still not vaccinated against Covid-19.

A plane carrying the No. 1-ranked player touched down in his native Serbia, closing at least the first chapter in a dizzying drama that has resonance in the world of elite sports, Australia's pandemic politics and the polarized debate over the coronavirus shots.

A handful of fans waving the Serbian flag greeted him at Belgrade's airport. Djokovic has an almost iconic status in Serbia, and many there felt he was poorly treated by Australia.

But his troubles may not be over yet: He could be barred from the French Open this year, under a new law intended to exclude the unvaccinated from stadiums and other public places. Much could change between now and the start of the Grand Slam tournament in late May, but that raised the spectre that the recent saga in Australia would be not just a blip but an ongoing challenge for the athlete, who is increasingly being held up as a hero by the anti-vaccine movement.

A member of the French Parliament, Christophe Castaner, said that the new law will apply to anyone who wants to play in the French Open — a reversal of earlier plans to create a "bubble" around the tournament.

"To do your job, to come for pleasure or leisure, to practice a sport, it will be necessary to present a vaccine. This will be valid for people who live in France but also for foreigners who come to our country for vacation or for a major sports competition," Sports Minister Roxana Maracineanu told BFM television on Monday.

But some details of the law are still being hashed out — including how it will deal with people who have recently recovered from Covid-19, as Djokovic says he has. The question is how recent the infection has to be to qualify for an exemption to vaccination rules.

Djokovic is also the defending champion at Wimbledon, which begins in late June. But so far, England has allowed exemptions from various coronavirus regulations for visiting athletes, if they remain at their accommodation when not competing or training. The U.S. Tennis Association, which runs the U.S. Open, has said it will follow government rules on vaccination status.

It's also not clear when Djokovic could head back to Australia. Deportation can lead to a three-year ban on returning to the country, although that can be waived, depending on the circumstances.