Pep Guardiola wants to extend Brahim Diaz's contract by "four or five years" but admits Manchester City will be powerless to stop him following Jadon Sancho out the door.
Diaz, 19, is out of contract this summer and City manager Guardiola says the club "will do absolutely everything" to keep the Spain U21 international at the club.
Sancho has become an England international after leaving City for Borussia Dortmund last year, with Guardiola admitting the club were desperate to keep hold of him.
But Guardiola played down concerns City will continue to lose their best emerging talents due to limits on their first-team involvement.
Asked about Diaz's contract situation, Guardiola said: "It's the same as Phil [Foden] and Sancho, the academy has to be proud. It is a signal we are working really well.
"We want him, we want to extend his contract four or five years - we will do absolutely everything, but it's in his hands.
"My advice if he doesn't want to stay he has to leave. It's simple.
"We protect him - the same with Jadon, Phil - but he has to decide. It's no more than that."
Guardiola does not expect Kevin De Bruyne to be ready to return from injury against Bournemouth on Saturday and said there will be late assessments over the fitness of Bernardo Silva, Ilkay Gundogan and Gabriel Jesus.
The City boss admitted he may have to "freshen up" his team with the club set to play 10 games between December 1 and January 3.
But game-time will not necessarily become more available for Diaz, who has made just three appearances this season - none of which have come in the Premier League.
"All we can do is speak with their families, we don't lie to them, tell them how complicated it is in some periods," Guardiola added of Diaz.
"Maybe they visualise he's going to play in other places, maybe it happens, maybe not."
Guardiola admitted City are themselves guilty of "going all round England to take players", adding that "the market is the market".
But he added: "They [academy players] cannot say we didn't do everything to look after them, and their families, as human beings and football players."