Sports_Fanatic
Assistant Pro
But you're still talking really small to minimal risk compared with contact/close quarter sports - the players are maintaining a significant distance apart and will be played outdoors (assuming fitness centres still closed) so the main route of catching it is gone around breath/spray on to you.
It's a physical activity so unlikely to have many playing with actual symptoms so the risk is around those who are at the early stages and don't show signs.
To transfer it on to the ball they'd need to have Covid 19, sneeze directly on to it (you don't really get that close to a ball during breathing), or on to hands, which then hold the ball and are picked up by the other person who would then need to wipe their face. And that could be stopped by using own balls to serve (just use a sharpie on them), flicking it up and hitting with a racket to begin rallies or just being aware and using hand sanitiser after rallies/play. There isn't much in the way of studies showing transfer in this manner (i.e. from surfaces) to be significant threat and to my knowledge nothing around transfer via sweat, and acknowledgement that it struggles more outdoors as well.
Edited - I'd expect the benefit of allowing this activity with precautions is much higher from both physical and mental than the Covid risk but also it presumably encourages people to gather in a way that maintains social distance than perhaps two friends meeting up in a house and chatting without remembering to keep 2ms apart.
then let the booking frenzy begin 
