Not really for us to decide, how it will work but just an idea. Also it depends in all honesty with regards to the stars of players. If you have a squad and a 5* player isn't being used for whatever reason why should he not be able to go out on loan? (he still might be the worst player in your squad and not being used!?)

Although your argument about important matches may be true this is where the separation of loan list & Transfer list comes into play you may not want to get rid completely for one reason or another therefore wold only place him on the loan list and not transfer list.