The odds makers at SportsBettingDime crunched the numbers and present a chart on the probability of being infected by SARS-Cov-2 at a fully attended sporting event based on date. Their calculations show that it really depends on the city, the venue, and the start date. Looking at Fenway, for example, waiting until July 1 instead of June 1 would cut the infection rate by 90%.

Of course, starting with minimum crowds instead of a packed house would help as well.