NBA, NFL, NHL, MLB, PGA.
Indoor enclosed spaces.
If you’re gonna continue to use the locker rooms, film rooms, team meeting rooms, weight rooms, trainer rooms, whirlpool rooms, massage rooms…..you’re gonna have to limit the number of masked players that can be in at one time or you’re gonna have to close those spaces and move everything outdoors.

Otherwise, transmission will continue and expand as you add to the frequency and number of players that are in these spaces all at once as games are added to practice sessions.