sell them all, and wait for next season to sign the one you want to keep. you have the 7 first days of next season to resigne them with lower money.
All you need to keep is 14 player at the end of season (incluse the ones exprired contract) and next season you have for free some crap 2* player 32-33 yo(they will be retired soon) if you have less than 14 players(exclus exprired contract)