Fulham midfielder George Williams could be out for up to six months after suffering a ruptured anterior cruciate ligament.
The 19-year-old Wales international damaged his knee while on loan at MK Dons, where he was supposed to stay for the rest of the season.
In a club statement today, Fulham said: "[Williams] had successful reconstructive surgery on Saturday evening in London and will now undergo a four to six month period of rehabilitation."
Williams, who extended his deal with Fulham until 2018 earlier this year, has won five senior international caps with Wales.