West Ham midfielder Pedro Obiang is expected to miss the rest of the season after a knee operation.
The 25-year-old Spaniard suffered medial ligament damage during West Ham's FA Cup defeat at Wigan on January 27.
The news comes as a fresh blow to manager David Moyes, who was unable to add another holding midfielder to his squad in January and is still battling with a lengthy injury list.
Hammers head of medical Gary Lewin told the club website: 'Pedro has undergone surgery to repair the medial collateral ligament, and we're delighted with how it went.