The Football Association is examining footage of Leicester's Danny Drinkwater appearing to elbow Watford's Valon Behrami.
The Foxes midfielder clashed with Behrami in the 67th minute of the Hornets' 2-1 Premier League win at Vicarage Road on Saturday.
Referee Neil Swarbrick took no action during the game but the FA, having been alerted to the footage after it ran on social media on Sunday, may act once they discover if the official saw the incident.
If the FA decides there is a case to answer then Drinkwater, who was booked in the game, could face a three-game ban for violent conduct.