Kevin Nolan suffered a broken toe during Monday night's derby against Tottenham, West Ham have confirmed.
The captain collided with Mousa Dembele during the first half of the 3-2 defeat, exacerbating a long-standing problem.
Nolan is out of this weekend's trip to Stoke and will instead undergo intensive treatment, but it is not yet known how long he faces on the sidelines.
West Ham assistant manager Neil McDonald said: "His toe's very, very sore. He's had problems in the past with it - all season really - and he got a really good kick on it.
"I'd imagine he'll not be available for Saturday and we'll see how the results come back and we'll see where he's at.
"He has been playing through the pain barrier. We'll assess it in the next couple of days."
West Ham have 15 days between the visit to the Britannia and their next game - away at Chelsea on 17 March.
Manchester United's continued involvement in the FA Cup means their trip to east London - originally scheduled for 9 March - has been postponed.