Sunderland midfielder Jan Kirchhoff will miss "a minimum of six weeks" after suffering a hamstring injury, the club have confirmed.
Kirchhoff, 26, was stretchered off during the Black Cats' 1-1 draw with West Bromwich Albion on Saturday.
A scan has shown the extent of the injury means the former Bayern Munich man will be sidelined for up to eight weeks.
The news will come as a blow to Sunderland manager David Moyes, whose side sit bottom in the Premier League having earned just two points from their opening seven games.
Kirchhoff joins Adnan Januzaj in being unavailable, the Manchester United loanee suffered ankle ligament damage during the 3-2 defeat against Crystal Palace and will be out for a similar amount of time.