Actually the chances are at near certainty level if we were to restart now. If we assumed 50 players and staff at each of the PL teams' training grounds, 20 clubs, that's about 1000 people. The death rate in the population at large for people under 40 is pretty low, maybe 0.2% I think? So that would be 2 deaths if everyone got it. Not too bad, particularly as it's unlikely everyone gets it. However, the rate of people who need intensive care treatment is at least double that, probably a lot more. So if we assumed for the sake of argument that 25% of these people got the virus, we'd expect a minimum of one person to go to the ICU and probably a lot more.
Now if you go to the ICU, and particularly if you're put on a ventilator, your recovery is not straight forward. Most people take months to recover, in the worst cases up to around a year to 18 months. And we still don't actually know for sure whether it is likely to cause permanent lung damage or just temporary. I would imagine a loss of even 5% of lung capacity as an athlete is a pretty big issue, and it seems at this point like it can be a lot more in some cases.