Andrew Castle speaks on Novak Djokovic medical exemption Andrew Castle said he is not surprised by the reaction that followed after Novak Djokovic received a medical exemption for the Australian Open but added there's surely a valid reason for why his application was successful. "We don't know what Djokovic's medical exemption is and we'll never know because it's private," Castle told BBC Radio 5 Live. "But he must have one. We knew this would happen when exemptions were announced. I'm not surprised [by the reaction] but what I will say is, it's not unfair because he satisfied two independent panels. "Is he giving the world of tennis the correct lead? It's arguable. It doesn't look like he's broken any rules, he's satisfied the independent panels so we're once again left arguing over another Covid-related matter. "I can understand the Australian public being furious. They've been to hell and back and if the crowd boo him - which I think they will - he will put it aside and become the favourite to win. No-one is arguing about his tennis, the concern here is leadership and the example he is setting, but it's not mandatory to have the vaccination."