Spartak Moscow will be without captain Alex for the UEFA Champions League visit of Chelsea in Group F on Tuesday.
The Brazilian playmaker is a key member of head coach Valery Karpin's squad, although he will be missing at the Luzhniki Stadium.
The 28-year-old sustained a thigh injury in Friday's 3-0 win over Alania and will need a week on the sidelines recovering from the blow.
"Medical tests, which were done on Saturday, revealed a minor tear," confirmed Spartak coach Karpin.
"He'll need about seven to 10 days to recover."
Spartak have six points from their opening two games and Karpin is not getting carried away with the team's early success.
Chelsea are their hardest opponents in Group F and ex-Russia international Karpin knows keeping the likes of Nicolas Anelka and Didier Drogba quiet will be crucial to their quest.
"We had a great start, probably better than some of our fans had expected," he continued.
"But we all know that beating Chelsea would be a totally different proposition from what we had before. So we're not getting carried away by any means.
"I don't want to predict the result. We have made a good start and are well positioned in the group now. We will need to put the handcuffs on (Didier) Drogba and (Nicolas) Anelka."