Real Madrid goalkeeping coach Luis Llopis, referred to as the "guardian angel" of Keylor Navas, has left the club to join Real Sociedad.
Llopis worked with Navas at Levante before becoming part of Madrid's staff, helping the Costa Rica goalkeeper to come through some difficult spells to produce key saves.
However, after Zinedine Zidane resigned as coach and was replaced by former Spain national coach Julen Lopetegui, Sociedad confirmed that Llopis was joining their goalkeeping set-up.
Lopetegui, a former goalkeeper, had been expected to retain both Llopis and Zidane's fitness coach Antonio Pintus, but will now need to add at least one new specialist to his staff.
Navas has dealt with speculation over his future through four seasons at Madrid, with Bernabeu chiefs again reported to be considering replacing him with Manchester United's David De Gea, Roma's Alisson or Chelsea's Thibaut Courtois.
Last week, the 31-year-old said Lopetegui had been interested in signing him for Porto when he left Levante in 2014.
De Gea's unconvincing displays for Spain at the World Cup, in which he has conceded five goals from six shots on target in three games, have led to speculation that he could be replaced by Kepa Arrizabalaga for Sunday's clash with hosts Russia.
Athletic Bilbao's Kepa, 23, almost joined Madrid in January only for Zidane to come out against president Florentino Perez's plan to pay his €20 million release clause.
Navas, meanwhile, impressed despite Costa Rica's elimination in the group stages, with a reflex stop from Brazil star Neymar standing out.
Last week, Madrid announced that they had signed 19-year-old goalkeeper Andriy Lunin from Ukrainian club Zorya Luhansk for a reported initial fee of €8.5m.
The futures of Madrid's other two senior goalkeepers, Kiko Casilla and Luca Zidane, are currently unclear.