Rehab group still have contact with other players and staff who then in turn have contact with other players and staff.
For this not to be an issue in regards to playing this match on Friday as scheduled it has to be a player who has zero contact with other players and staff or they all return a negative result. Having said that even returning a negative result might not be enough given that this virus sometimes doesn't show up till a few days later and presumably they've all be tested just today.