Chelsea are set to send promising defender Mamadou Sarr on loan to Real Sociedad, with the Senegal international undergoing a medical in Spain as the move approaches completion. The season-long deal is not expected to include an option to buy, meaning Chelsea will retain control of the highly rated centre-back’s future.

The decision is understood to be driven primarily by playing-time considerations. Chelsea believe Sarr has a bright future at Stamford Bridge, but with intense competition for places under new manager Xabi Alonso, regular first-team minutes could be difficult to secure in London.

Sarr was recalled from a loan spell at sister club Strasbourg midway through last season but made only three Premier League appearances after returning to Chelsea. Rather than see his development stall, the club now believes a full season of regular football at Real Sociedad will be more beneficial.

The 20-year-old defender, who stands at 1.94m and can operate on either side of central defence, is regarded as one of the promising young defenders in European football. Real Sociedad intend to use him primarily on the left side of their defence, where his physical presence and ability to play out from the back could strengthen the team.

For Chelsea, the move also helps ease a major congestion at centre-back, with Alonso looking to reduce his senior defensive options to around four or five players. Sarr’s temporary departure should allow him to gain valuable experience while Chelsea continue to monitor his progress ahead of a potential return to Stamford Bridge next summer.

Could a season of regular football at Real Sociedad be the key to turning Mamadou Sarr into a future Chelsea first-team star?