The England forward signaled Arsenal's 2-0 lead to Spurs' fans as he was being taken off the field in a stretcher following a knee injury that will rule him out of the World Cup this summer.
According to the BBC, however, Arsenal boss Arsene Wenger said that Walcott was reacting to having coins thrown at him, while the FA said that Walcott has been 'reminded of his responsibilities'.
The FA stated that it has contacted both Arsenal and Tottenham over objects thrown onto the pitch from fans in both a home and an away section at Emirates Stadium, at different times during the game, 'to identify those responsible and support the strongest sanctions available, including life bans'.
Wenger insisted that Walcott, who was pelted with objects from supporters in the Spurs end after he made the gesture, did not deserve to be punished.
Arsenal announced that Walcott, who missed two months of the season with a stomach injury and has scored five Premier League goals since returning in November, would be out for at least six months after rupturing the anterior cruciate ligament of his left knee.