Pep Guardiola insists Manchester City have done everything to persuade academy graduate Brahim Diaz to stay at the club.
Diaz, the highly-rated 19-year-old attacking midfielder, is out of contract at the end of the season and was this week reported to be ready to sign for Real Madrid.
The Spaniard would be free to speak to other clubs from next month. Diaz has been used sparingly by Guardiola and not featured since scoring twice against Fulham in the Carabao Cup on November 1.
"The case of Brahim is very simple," City boss Guardiola said. "We want him to stay, we want to extend his contract for four or five years and we'll do absolutely everything to keep him here.
"But, as I said before, it's in his hands. My advice is - if he doesn't want to stay, he has to leave."
City have been hoping to tie up young talents such as Diaz and Phil Foden to new deals.
However, Jadon Sancho last year opted to leave for Borussia Dortmund and has since been rewarded with first-team opportunities in the Bundesliga and full international recognition with England.
Guardiola will not attempt to stand in Diaz's way should he want to leave but he warns there are no guarantees of action elsewhere either.
"They cannot say we don't do absolutely everything to take care of them and their families, like a human-being, like a person, like a football player," he said.
"It's incredible how the academy works with these guys, taking care of them, teaching them what they need to be a high standard for a long time but at the end they decide. The market is the market.
"We cannot push more than we pushed with Brahim, for example, or with the other ones. At Barcelona there were many players, for example Cesc Fabregas, who wanted to leave and go to Arsenal. It happens, always, this situation.
"All we can do is speak with the families, find out what they want to do with these guys. We tell them the truth, how complicated it is in some periods.
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"How many young players are playing at 18 or 19 in the big clubs in Europe and the world every week? Maybe one - [Kylian] Mbappe, but not the other ones.
"Maybe they visualise they are going to play and believe in other places they are going to play. Maybe, maybe not. We will see."
City continue their Premier League title defence as Bournemouth visit the Etihad Stadium on Saturday.
The leaders have a strong record against the Cherries, having won all six of their previous Premier League meetings, scoring 21 goals and conceding just two in the process.
Guardiola claims that counts for nothing with Eddie Howe's side currently sitting eighth in the table.
"I don't care about the records and the stats," he said. "They are in the past. The good results we've had don't allow us to start 3-0 up.
"They are stable and a good team and have a lot of years playing with the same manager. It will be a tough game."