Queens Park Rangers midfielder Alejandro Faurlin could be sidelined for six to nine months after suffering a third anterior cruciate ligament injury in as many seasons.
The 28-year-old landed on his knee in the second half of QPR's 1-0 defeat to Burton Albion in the Capital One Cup on Wednesday.
Scans have revealed the extent of the injury, which is similar to the one that he suffered in November and further back in January 2012.
QPR's head of medical services Peter Florida James told the club's official website: "We're all absolutely devastated for Ale. It looked so innocuous on Wednesday night, so this has come as a massive blow for us all.
"The knee itself stayed pretty stable, but the scans have since revealed his ACL graft has ruptured. If he has a repair it will be a six to nine month injury, which is absolutely devastating for all concerned."
Manager Harry Redknapp added: "We're all desperately saddened and disappointed for Ale. He is a great man and player, and he's suffered terribly bad luck over the last few years with injuries. We will, of course, do everything we can to support him and help him back on the road to recovery."
Faurlin has been a QPR player since 2009.