West Ham have been fined almost €100,000 by FIFA after selecting Diafra Sakho following the striker's withdrawal from the Africa Cup of Nations.
The striker failed to join up with the Senegal team early last month - claiming a back injury - but then played for the Hammers in their FA Cup win over Bristol City.
West Ham responded to FIFA's decision, which read: "The club and the player have received the decision and will now be focusing their concentration on the game against Manchester United on Sunday.
Bristol City said in its own statement: "The club is disappointed with the penalty handed down by the Fifa disciplinary committee and is considering its options."