US Open 'very hopeful' unvaccinated Novak Djokovic can play

Novak Djokovic of Serbia plays a forehand return to Roberto Carballes Baena of Spain during their first round match at the Australian Open tennis championship. (Aaron Favila/AP)
Novak Djokovic of Serbia plays a forehand return to Roberto Carballes Baena of Spain during their first round match at the Australian Open tennis championship. (Aaron Favila/AP)