In some ways sports will be the guinea pig. Heck, the NFL should probably be signing up for the vaccine trials.
It seems inevitable that 30% or even 50% of MLB will eventually test positive for the virus, the question is will any of them get seriouslly ill, and will they endanger others? A hotel or stadium worker who is at-risk (or has family at-risk) can't just quit their job (or get unemployment now that things are opening up), and they are being asked to take something greater than the risk an Amazon or supermarket employee or bus drive is taking, since baseball maybe be a business, but it's not essential.
We might never know the details but they should be contact tracing the Phillies people. Who were the players who went to a bar? Who was hanging out with the Toronto player? Did all the others still get it from them at the complex in spite of protocols, or via community spread in other ways?