West Ham have confirmed forward Ricardo Vaz Te has undergone a successful operation on a shoulder problem.
The 26-year-old sustained a dislocated shoulder during the defeat by Arsenal on 6 October, and is expected to be out of action for three months.
A statement from the Hammers read: "West Ham United can confirm that Ricardo Vaz Te underwent successful shoulder surgery on Monday evening as he continues his recovery from the dislocation he suffered during the Barclays Premier League fixture against Arsenal on 6 October.
"Head of Sports Medicine Andy Rolls and his medical team have been working with Vaz Te since the match to determine the right course of treatment and it was decided that keyhole surgery was the best long-term solution to ensure there were no further complications.
"After being kept in hospital overnight for observation, Vaz Te will now start his rehabilitation, which is expected to take up to 12 weeks."
The Portuguese winger has scored one Premier League goal this term - in the 2-1 victory over London rivals Queens Park Rangers.