West Ham have confirmed the Football Association are investigating a comment made by Ravel Morrison on Twitter.
The 19-year-old midfielder, who moved to Upton Park from Manchester United on transfer deadline day, is reported to have made a homophobic comment in response to another Twitter user.
A statement on West Ham's official website read: "West Ham United are aware that the FA have written to Ravel Morrison asking for his observations regarding comments on Twitter.
"Ravel and the club will co-operate fully with the FA's request and have until Monday evening (February 13) to respond.
"There will be no further comment from West Ham United or Ravel at this stage."