If you are going to allow provisional players, you need to allow them for EVERY game.
I can see it happening now, team with Mahomes and Hill get to select provisionals, opponent with Matt Ryan and Julio. Monday Morning, Matt Ryan tests positive, Falcons/GB game postponed as a BYE, That guy will be stuck with 2 zeros.
You allow provisionals, you better allow it for every player for every game. Only way to do that is to list you QB1, QB2, RB1, RB2, RB3, RB4, RB5, WR1,WR2 etc.
Then players move up in the ranking only if their game is not played.
It's already unfair for for teams who had players play on Thursday. One guy has Watkins and Hill, M Thomas injured, Slayton and Jeudy. He cannot set provisionals for both Watkins and Hill. All lists should have to be submitted before the weeks games start.
At this point I say do nothing and let the cards fall where they may.