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It is be a good idea to for the management to support Flick and allow him bring in players of his choice that he knows will perform well under him. Since Barcelona have released those three players, it means that they must have replacement for them.
It is not going to be easy for Barcelona next season because their rival Real Madrid is a big threat to them and Barcelona force is not as strong as their with Mabppe that have joined the team. Barcelona should play with passion and make sure that they improve their performance. Maybe they might be lucky to win a trophy next season.
Bringing in some experienced players is a good idea for Hansi Flick, but I can't really believe it will be realized considering that Barcelona has quite a lot of players in its squad at the moment. Several young players have returned from loan spells and they could be ready to take their places next season if Hansi Flick gives them confidence.
As far as we can see, Barcelona can play with its young squad. There are plenty of talented young players set to become stars under Hansi Flick next season, but there have been recent rumors about Barcelona's interest in signing Jaden Philogene from Hull City. If Barcelona management is patient and Hansi Flick does not demand too much, then this young Barcelona squad will be able to compete in every available competition. I'm definitely curious about that, but the potential is really good.