Mamadou Sarr joined Strasbourg from Lyon in August 2024
Alex Fletcher
BBC Sport journalist
Chelsea have signed defender Mamadou Sarr from partner club Strasbourg for £12m.
The 19-year-old Frenchman has signed an eight-year deal and is eligible to play at this month’s Club World Cup in the US.
Enzo Maresca’s side start their tournament against LAFC on 16 June, before facing Brazilian side Flamengo on 20 June and rounding off the group stage against Tunisian champions ES Tunis on 25 June.
Chelsea and Strasbourg agreed a deal for Sarr in January, with a view to completing the transfer this summer.
He made 28 appearances in all competitions for Strasbourg this season. They finished seventh in Ligue 1 to book a spot in the Conference League play-offs.
Like Chelsea, Strasbourg are owned by American Todd Boehly and Clearlake Capital under the BlueCo umbrella, and Sarr’s is the first transfer between the clubs.
The signing is Chelsea’s fourth of the summer, following the arrival of Liam Delap for £30m from Ipswich Town, Estevao from Palmeiras for £29m and Dario Essugo from Sporting Lisbon for £18m.
BBC Sport understands that Chelsea are pursuing Borussia Dortmund winger Jamie Gittens.
Winger Jadon Sancho left Chelsea at the end of the season to return to Manchester United following his loan deal.
