Husain Abdullah intercepted a pass from an opponent and dashed to the end zone to score
A Muslim NFL player has received a penalty after celebrating a touchdown by dropping to his knees in prayer, US media say.
Husain Abdullah scored for the Kansas City Chiefs as they defeated the New England Patriots 41-14.
He slid on his knees then pressed his forehead against the end zone grass.
Although the move violated "excessive celebration" rules, National Football League (NFL) officials have been criticised on social media.
Comments on Twitter and other sites said there were plenty of Christian players who marked their scores with signs of deference or religious tributes.
Abdullah told reporters afterwards: "If I get a pick, I'm going to prostrate before God in the end zone."
According to the NFL rulebook, under a section covering unsportsmanlike conduct, "players are prohibited from engaging in any celebrations or demonstrations while on the ground".
It was not clear whether the penalty had been given for bowing in prayer or for sliding when he scored.
Abdullah is said to be a devout Muslim
Abdullah, 29, told the Kansas City Star newspaper that game officials had said nothing to him at the time but the Chiefs' coach had told him he had been penalised for sliding.
"For me, I just got a little too excited," he said.
Abdullah, a devout Muslim, skipped the entire 2012 season to go on a Hajj pilgrimage to Mecca with his brother, another NFL player.