From the Cov Tel article
However, CoventryLive understands that despite the latest round of negative results, the knock-on effect of previous positive cases within the group will have a big impact on the squad head coach Lee Blackett will be able to select.
This is due to players who have directly tested positive for coronavirus and having to self isolate and also players who have been in close proximity to team-mates and coaches who have tested positive.
Not sure what this actually means
I'm presuming Wasps and PHE are applying the letter of the law. Regardless of whether has someone tested negative, if they have been in contact with someone that has been tested positive, they then have to self isolate for 10 (or is it 14) days.
In theory we could have 37 squad members testing negative but only 25 available for selection for the final