Jordi Cruyff says Matthijs de Ligt and Frenkie de Jong should use Holland teammate Memphis Depay as an example before leaving Ajax.
De Ligt and De Jong are both Barcelona targets but Cruyff, currently coaching Chinese side Chongqing Lifan, wanted against moving too soon.
Both players are still young and Cruyff suggested they take a look at how Depay's move to Manchester United worked out before jumping ship.
Depay failed to make the grade at Old Trafford after leaving PSV but has refound his form in France with Lyon in the last two season.
"Four years ago, [Depay] went from the world stage to nothing. At Manchester United it seemd that he still wasn't ready," Cruyff said. "He's got back on track at Lyon and is giving more to the national team."
Holland beat Germany 3-0 at the weekend. De Ligt didn't have a standout game but he improved as the match went on, showing his authority despite only being 19.
Cruyff said: "De Ligt is a really talented defender, who is still growing. He's doing so impressively, but against Germany it was clear he has a long way to go, in terms of performance.
"De Ligt, De Jong and Donny van de Beek should all take international teammate Memphis Depay as an example [when considering their futures]."