CSKA Moscow goalkeeper Igor Akinfeev faces a lengthy spell on the sidelines after suffering a serious knee injury.
The Russia international sustained the knock in his club's 2-2 league draw against Spartak Moscow at the weekend and was forced to leave the pitch after 30 minutes of play following a collision with Welliton.
It's not yet known how long the 25-year-old custodian will be sidelined, but the Champions League hopefuls fear Akinfeev could be out of action for up to six months.
"Judging by the mechanics of the injury and the symptoms, Akinfeev has ruptured cruciate ligaments," CSKA coach Leonid Slutsky said, according to Uefa.com.
Akinfeev will not only miss the Champions League group stage matches against Inter, Lille and Trabzonspor if the first diagnosis is confirmed, but will also be forced to watch Russia's remaining Euro 2012 qualifiers from the stands.