Pep Guardiola understands when players decide to leave in search of regular playing time.
Manchester City forwards Raheem Sterling and Gabriel Jesus are expected to be sold this summer.
And they could be followed by defensive duo Nathan Acke and Oleksandr Zinchenko, while midfielder Bernardo Silva would like to move to Spain.
City boss Guardiola said: “The most complicated thing to manage in a team is having players who don’t play and keeping them happy.
“There is no solution – that’s why good players leave their teams because they want to play.
“I can’t retain a player who doesn’t play just because he has a contract.
“I told my players that I want to see them happy. We have known each other for a long time and if someone is sad he has to leave.
Jesus, 25, is set to join Arsenal for £45m for fear of being limited by the arrivals of Erling Haaland and Julian Alvarez.
Sterling, 27, has similar concerns and wants Chelsea, who have also inquired about AK and Zinchenko.