Chelsea's Raheem Sterling could face a ban after appearing to throw an object at Tottenham fans during the 4-1 London derby win on Monday night.
The Football Association (FA) is investigating footage of the incident, which was posted on social media.
If Sterling is found guilty of misconduct, he could face a ban of up to three matches.
The footage showed an object striking Cole Palmer in the leg after he equalized through a penalty.
As the players moved away to restart the match, Sterling appeared to bend down to pick up and throw the item back into the crowd before joining his teammates.
The incident was not spotted by officials but is now being reviewed to determine whether any action needs to be taken.
Sterling was outstanding in Chelsea's victory, and his assist on the game-winning goal was the difference against a resolute nine-man Spurs defense.
Different players have been previously banned in a case like this.
Tottenham's Richarlison received a one-game ban in May 2022 after scoring a goal for Everton against Chelsea and then throwing a lit flare back into the crowd.
Didier Drogba threw a coin at Burnley fans after their team lost in the Carabao Cup in 2008, leading to a three-match suspension.