Middlesbrough midfielder Didier Digard is out for three months following the injury suffered in Saturday's 0-0 draw with Wigan Athletic.
Digard was hurt in a challenge with former Boro midfielder Lee Cattermole and was stretchered off midway through the first half at the Riverside.
Scans have shown that the French midfielder has damaged medial ligaments in his right knee and suffered a rupture to the quadriceps muscle in his left leg.
He is now expected to be out until May and could face a battle to pull on a Boro shirt again before the end of the season.
"Didier Digard faces a 12-week lay-off after confirmation that he suffered a partial rupture to the quadriceps muscle of his left leg and a partial tear to his medial ligament of his right knee during Saturday's game," read a statement on the club's official website.
"The French midfielder will need to undergo extensive rehabilitation to overcome the quad injury and it is anticipated that he will take around 12 weeks before he is ready to return to playing.
"He visited an orthopaedic specialist on Monday when details of the double injury were confirmed."
Digard has scored once in 25 appearances for Boro in all competitions since moving to Teesside from Paris St Germain last summer.