Shane Long will miss the Republic of Ireland's clash against Russia on Tuesday through injury.
The West Bromwich Albion striker sat out of his country's 0-0 draw with Slovakia on Friday with a calf strain, and hasn't been able to recover in time for their match at the Luzhniki Stadium.
Giovanni Trapattoni's side are currently second in Group B, two points behind leaders Russia, but are joint on points with Slovakia.
While West Brom are yet to pick up any points in the Premier League this season, Long has impressed, scoring two goals in three games.