I've said it on another thread and my answer to this is that the players would be on 'pre-contract'
A 99% player get's signed in the last week, you can't use him that season, but at the start of next season he is your player, still at 99%, still the same age etc.
A very good way to build next seasons team, you get the whole week to plan it and not have your tokens tied up in bids on the first day of the new season, wondering whether the bid will be accepted.