Kansas City Chiefs safety Husain Abdullah received a 15-yard unsportsmanlike conduct penalty Monday night when he dropped to the ground in Muslim prayer during the fourth quarter of his team’s 41-14 victory over the New England Patriots. After returning an interception 39 yards for a touchdown, Abdullah slid to his knees, then bowed toward the Muslim holy city of Mecca, but NFL rules forbid players from “going to the ground” to celebrate a touchdown.

The game’s head referee cited “going to the ground” as the reason for the unsportsmanlike conduct penalty against Abdullah. After the game, Abdullah told reporters that he was likely penalized for his slide, rather than the prayer itself. “For me, I just got a little too excited,” Abdullah said, according to the Kansas City Star. “I think it was for the slide.”

Specifically, Rule 12, Section 3, Article 1 (d) of the NFL rulebook states “players are prohibited from engaging in any celebrations or demonstrations while on the ground.” Mike Pereira, the NFL’s former vice president of officiating, said in 2013 that the rule isn't meant to penalize players for praying after a touchdown. However, the call appears to be left to the officiating crew’s discretion -- Chicago Bears wide receiver Brandon Marshall wasn't penalized for dropping to his knees after scores against the San Francisco 49ers and the Green Bay Packers, Deadspin notes.

Officials didn't approach Abdullah with an official explanation for the penalty. However, he said Chiefs head coach Andy Reid talked to him after the play. “[Reid] said, ‘you can’t slide,” Abdullah said.

“When you go to Mecca, you should be able to slide wherever you want,” Reid told reporters after the game. “We’ve got two priests in here. They’d probably vouch for me.”

Abdullah’s agent, CJ LaBoy, took to Twitter to react to the unsportsmanlike conduct call against his client. “If the NFL tries to fine [Abdullah] for his TD celebration there’s going to be some problems,” he wrote.

A devout Muslim, Abdullah missed the entire 2012 NFL season to undertake the hajj, a spiritual pilgrimage to Mecca that is considered one of the Five Pillars of Islam, USA Today reported. For the 29-year-old, the post-touchdown prayer was the fulfillment of a promise he once made to himself.

“If I get a pick, I’m going to prostrate before God in the end zone,” he said.