Chelsea have announced Marco van Ginkel will be out for six months after undergoing knee injury.
Van Ginkel, a £8.4m summer signing from Vitesse Arnhem, suffered the knee injury during the Capital One Cup win over Swindon Town.
The Dutchman - making only his second Chelsea start following his summer move - went down after a challenge from Alex Pritchard and hobbled off the pitch in the 10th minute.
A club statement said: "Chelsea Football Club can confirm Marco van Ginkel successfully underwent anterior cruciate ligament surgery today (Thursday).
"The 20-year-old midfielder is expected to be out for approximately six months."