The Football Association has written to West Ham's Ravel Morrison over comments made on Twitter.
The FA has given the 18-year-old former Manchester United midfielder until Monday to respond.
A statement on the West Ham website read: "We are aware the FA has written to Ravel asking for his observations regarding comments on Twitter.
"Ravel and the club will co-operate with the FA's request and have until Monday evening to respond."
It continued: "There will be no further comment from West Ham United or Ravel at this stage."
Morrison arrived at Upton Park in January on a three-and-a-half-year deal after moving through the youth ranks at Old Trafford.