@bruceyg; players drop out every year due to heat and to illness / infections - even the likes of Djokovic have at times struggled with Melbourne's Summer heat.
I note that three of those named have recently experienced Covid infections: Tomic, Kyrgios & Basilashvili.
You'd have to be an optimist or a Covid-denier to think that you could get the virus and not be affected during extreme physical exertion.
