Rayo Vallecano have blocked Leeds United's approach for manager Andoni Iraola, Spanish football expert Guillem Balague has told BBC Sport.
He oversaw two victories against Barcelona last term and in November they beat champions Real Madrid 3-2.
Iraola was keen to speak with Leeds, who sacked Jesse Marsch on Monday, but was not granted permission by his club.
He was one of four candidates Leeds are considering to succeed the American, who was dismissed after seven successive games without a win.
Under-21s coach Michael Skubala took charge of Wednesday's 2-2 Premier League draw at Manchester United, when Leeds took a shock two-goal lead before the hosts levelled through Marcus Rashford and Jadon Sancho.