Fulham hope to have striker Brian McBride back in action within four months.
The 35-year-old dislocated his kneecap in the defeat to Middlesbrough earlier this month and travelled to America for surgery.
Head physiotherapist Jason Palmer expects McBride to return before the end of the year.
Palmer told the club's official website: 'His recovery will be a steady process in the early stages and we are hoping for a return sometime around Christmas.
'Brian was reviewed in the United States by the US national team's orthopaedic specialist, who Brian has known for many years through his involvement with the national team.
'Investigations confirmed he suffered a complete rupture of his quadricep muscle in the areas where the quadricep inserts into the patella (kneecap bone).
'Consequently he underwent a surgical procedure to repair and reattach the muscle. The surgery went very well and he has returned to complete his rehab with the medical staff here at Fulham.'
Fulham, who face Tottenham at home tomorrow, have signed defender Nathan Ashton on a two-year contract.
The 20-year-old was previously with Charlton and has also played for England Under-20s.
Midfielder Lee Cook, who arrived from QPR in the summer, is expected to return to training next week after a knee injury, with hopes of a return in mid-September.