My guess is that it's handled on an individual school or program level. I don't think NCAA and conferences don't have any rules or monitoring anymore, just "guidance" on how to handle testing, isolation, etc.
Hard to know for sure, but it sounded a little bit like Northwestern postponed their dual with Illinois last month because the team got hit with Covid and did a five day isolation. Some others thought it might have been ringworm, also plausible.