Chelsea have confirmed Marco van Ginkel faces six months on the sidelines after successfully undergoing anterior cruciate ligament surgery.
The Dutch midfielder, an £8m summer signing from Vitesse Arnhem, was forced off in the first-half of Chelsea's Capital One Cup match against Swindon on Wednesday night.
Chelsea feared he could miss the entire season with the knee injury, but the club statement indicates that Jose Mourinho hopes to have him back in the team by March.
The statement published on Chelseafc.com reads: "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.
"Van Ginkel suffered the knee injury during the first half of our Capital One Cup match at Swindon on Tuesday evening."
The Netherlands under-21 star has made two substitute appearances for the Blues in the Premier League so far this season, and was expected to feature heavily off the bench for Jose Mourinho's side.
The injury leaves Mourinho with Frank Lampard, John Obi Mikel, Michael Essien and Ramires as the club's first-team midfielders for the majority of the rest of the campaign - unless the Blues choose to strengthen in the January transfer window.