The Greek giants have approached City about taking Santa Cruz to Athens on a season's loan.
Santa Cruz's agent Jan Van Baal said: "If he leaves City would certainly want to get back a bit of their investment. He won't go for free.
"I could see a paid-for loan with an automatic option to buy. It's the fashionable solution, but that's for Manchester City to decide.
"There are some leads in the Premier League and abroad. He still has his admirers. I know that Marseille are interested and there have been a few discussions.
"It is an interesting destination. They are in the Champions League and they have a manager who is established. These are important factors.
'He has the profile for Marseille."