Under returning president Florentino Pérez, Real Madrid have made clear their intention to steer the club back toward its old Galácticos philosophy, and Haaland's name has been a constant fixture in that conversation for years.
The signals grew stronger recently after the striker's father, Alf-Inge Haaland, hinted at a possible blockbuster move in comments of his own, and Díaz has now gone further, citing Borussia Dortmund chief executive Hans-Joachim Watzke as his source.
Speaking in a Twitch interview, Díaz was unequivocal about what he had been told.
"I spoke with the president of Borussia Dortmund during the Real Madrid elections, and he told me that Haaland loves Real Madrid and that he will play there one day. But now isn't the right time for Haaland — it will be next summer or the one after," Díaz said.
Pep Guardiola left Manchester City at the end of last season after a decade in charge that brought 20 major trophies, with former Chelsea manager Enzo Maresca now installed as his successor at the Etihad. According to Díaz, City are not expected to lose their star striker in the same summer that saw Guardiola depart the club.
"I was told it's not currently possible, because City are entering a new era and he's the undisputed leader — and Haaland himself wants to enjoy this period and stay at City. But Haaland's time will come. Unless there's a radical turn of events, it won't happen this summer," he added.
Haaland, 25, still has a contract at City running until 2034, giving the club every legal protection against an unwanted departure regardless of how the speculation develops.
Given the scale of any potential deal and the timescales suggested, this looks set to remain a recurring storyline for Real Madrid over the next couple of transfer windows rather than an imminent transfer.