Queens Park Rangers midfielder Jermaine Jenas faces up to nine months on the sidelines after a training-ground injury.
The 31-year-old former England international was building up his fitness following a calf strain when suffered a cruciate ligament injury on Saturday.
Jenas, who has made 28 appearances for Rangers this season, scoring two goals, is likely to require surgery and could be ruled out for the rest of the year.
Rangers medical chief Peter Florida told the club website: "JJ has completely ruptured his anterior cruciate ligament in his right knee.
"We'll be taking him to see a specialist later this week to decide the next course of action.
"At this stage it would appear he'll require a full repair, which is likely to keep him out for between six to nine months.
"JJ is in fairly good spirits all considering. He's been unlucky throughout his career with injuries, but he's in a positive frame of mind.
"JJ does everything asked of him in terms of injury prevention techniques - but unfortunately he's just one of these very unlucky players when it comes to injuries."