N'Golo Kante is returning to Chelsea to be assessed by the club's medical staff after suffering a suspected hamstring injury while on international duty.
Kante was substituted in the 34th minute of France's 1-0 win in Bulgaria after picking up the injury.
He is expected to return to Chelsea by Tuesday night, and manager Antonio Conte will give an update on the midfielder's condition before their trip to Crystal Palace on October 14.
Chelsea already have concerns over the fitness of Alvaro Morata, who also picked up a hamstring injury in the Blues' 1-0 defeat to Manchester City before the international break. Morata is hoping to make his return at Selhurst Park.
Kante, who was today named on France Football magazine's shortlist for the Ballon d'Or, will miss France's World Cup Qualifier at home to Belarus on Tuesday night.