Chelsea have released an update on Christopher Nkunku’s injury which he suffered during the final pre-season friendly against Borussia Dortmund.

Statement from Chelsea reads: “Nkunku has sustained a knee injury which will rule the forward out for an extended period.

“The 25-year-old has undergone an operation and will now begin a rehabilitation programme with the club’s medical department.”

Nkunku suffered a knee injury in the 22nd minute of Chelsea’s final pre-season match against Borussia Dortmund in Chicago following a challenge from Mat Hummels.