Leyton Orient winger Dean Cox is facing a six-month spell on the sidelines after picking up an ACL injury.
The 28-year-old damaged the cruciate ligament in his right knee during a training session last week.
O's boss Ian Hendon admits that being without Cox, who has scored five goals in 16 appearances for the club so far this season, will be a real blow.
"He was running with the ball and looked like he got his foot stuck in the ground," he told BBC Sport. "We are devastated for him and it is a massive loss for us.
"Paul McCallum did a similar injury and now we've lost Dean. It is not anything we have done or an impact injury. They are accidents and they happen in football."
Cox, voted August's League Two Player of the Month following a string of impressive displays, has made 210 appearances for Orient since joining from Brighton & Hove Albion in 2010.