According to Real Sociedad official news, the club signs Mamadou Sarr from Chelsea on loan. 

Real Sociedad Official Announcement:

Real Sociedad and Chelsea FC have agreed to the loan of Mamadou Sarr until the end of the 26-27 season.

Mamadou Sarr (Martigues, 2005) is a right-footed centre-back accustomed to playing on both flanks. He is an international for Senegal, where, despite his young age, he has already won the Africa Cup of Nations and played in the 2026 World Cup. His imposing physique and vision will give the team a distinct advantage from day one.