Chelsea goalkeeping coach Christophe Lollichon admits they've been monitoring Reims No1 Edouard Mendy.
Mendy is being linked with a return to Marseille.
Lollichon told Le Parisien: “He has reached maturity, with a fairly unusual path, and it is all the more meritorious.
“Edouard Mendy is today, for me, the best goalkeeper in the Championship of France.
“He is what I call proactive, very influential goalkeeper… Reims really did a great job with him.
“Maybe at [Marseille] they could not detect the talent he had in him, but it was perhaps not the right time too.
“In any case, he's a great goalkeeper that we follow in the Premier League."