Inter Milan boss Jose Mourinho admits tough decisions need to be made if they're to compete for the Champions League next season.
"I only ever played with one system throughout my career, but I changed that in Italy," revealed the man who won the Scudetto at the first attempt.
"I realised the other teams all focus on tactics and can adapt to their opponents, so I had to adapt too without losing my own philosophy and way of approaching football.
"To win in Europe I think we need more balance. There has been so much talk of a squad with 25 players, but looking back we've had seven or eight who were crucial and almost always played. If one of those drop out, the team is no longer the same.
"The way to find balance is to change three or four players who were not crucial and find replacements who are of the same level.
"We need two midfielders, as with the diamond system we always tended to play with the same figures and when one was injured or suspended it caused huge problems straight away. Also we require a defender and a striker, as Adriano has left and others are out of contract.
"It is more difficult to change when you win, as the memories of great moments hold you back. You need to be a bit cold, to put those feelings aside and be rational when pruning the squad."