Marca concede that it’s difficult for Enzo Zidane to gain a foothold within the Real Madrid squad, and therefore an exit on loan was always a possibility. The presence of Aitor Karanka at Middlesbrough is always seen as a bonus to any Spanish related transfer, and therefore it makes some sense.
That’s not to say it’s true of course, just not ridiculous. It’s probably likelier that Zidane would go on loan in Spain, or France, and Karanka may feel the signing would represent one unknown quantity too many in his squad for the Premier League next season.
Marca don’t have anything of their own to add, and the story takes up a small section of page 8. Whilst they’re not rubbishing it, it doesn’t at this stage appear to be something they’ve heard about independently.
