Testing and removing positive cases should work, but if the test results take 3 days to come back it's pointless. The first Marlins cases we heard about was on Saturday, that means they tested positive in their Wednesday tests. These latest cases today would mean they tested positive Friday. So the latest 12 guys to get it had it before we even knew about the first 4. That's just never going to work. Other sports have been getting same day result. If you can determine someone is contagious and remove them within 24 hours of becoming contagious(every day testing with same day results) then you should be able to contain an outbreak and only have small pockets of cases at worst. Given these other 12 guys would have been positive on Friday I would not be shocked in the Saturday and Sunday testing results in everyone on that team being positive at this point. You're not weeding out cases if it takes you 3 to 4 days from the test to removal.