The independent panel ruled the Hammers forward had "exaggerated" and "dived" to earn his side a penalty against the Potters and becomes the second Premier League player to be charged over simulation.
In a statement from the FA read, the panel ruled: "In the incident in question, the player whilst running at speed in the opponent's penalty area took a final touch with his right foot away from the defender.
"It was at this point that he started to go to ground in an exaggerated manner, which included throwing his arms into the air in an unnatural way, before any contact with the opposing defender.
"In that split second he dived, before the contact from the defender who had in fact withdrawn from the challenge.
"It is not disputed that there was contact but the player anticipated this, dived towards the defender to initiate the contact and in reacting the way he did, successfully deceived the match official."