Middlesbrough midfielder Didier Digard faces 12 weeks on the sidelines with the injury suffered in Saturday's goalless draw against Wigan.
A visit to a specialist has confirmed a partial rupture to the quadriceps muscle in his left leg and a tear to the medial ligament in his right knee.
The 22-year-old Frenchman was carried off on a stretcher at the Riverside following a legitimate tackle by Boro old boy Lee Cattermole.
Middlesbrough manager Gareth Southgate said afterwards: "If I was on their side I'd be thinking he timed it just about right.
"Unfortunately Didier turned into him and got caught."