Raheem Sterling revealed a t-shirt memorializing a young footballer after scoring his second goal in a hat trick for England against the Czech Republic on Friday.
Damary Dawkins, a Crystal Palace youth team player who had been fighting acute lymphoblastic leukaemia for four years, died on Sunday aged 13.
Sterling’s t-shirt under his England jersey had a photo of Dawkins and the message "May your soul rest in peace."
But the tribute in the European Championship qualifier, which England won 5-0, could lead to action by governing body UEFA.
The laws of football state that "players must not reveal undergarments that show political, religious, personal slogans, statements or images, or advertising other than the manufacturer’s logo." The law introduced in 2014 states that an offending player has to be sanctioned by the competition organizer.