I have no idea how they got them and presumably neither do you. However, there are methods other than the "test kits" available that are low volume approaches. The issue with testing is *VOLUME*. These other methods don't involve the official CDC test that is being distributed and reproduced. Anything that can do PCR could theoretically be used. Those techniques just aren't valid/available/reliable for widespread use by RNs, etc.

The process is known: https://www.cdc.gov/coronavirus/2019-ncov/lab/rt-pcr-detection-instructions.html

The application of this in a private lab setting is workable, but not to testing 100,000 people off the streeet. There may be other methods I have no idea about.

In the end, I don't know how the players were tested. Does it have to do with their privilege and status? Almost certainly? But they may not be robbing tests from others as I think the OP and your question implies.