The FA have asked Cardiff City and manager Neil Warnock for further observations over his comments in relation to referee Andrew Madley.
Warnock was unhappy with Madley's decision not to book Watford striker Troy Deeney for his challenge on Cardiff goalkeeper Neil Etheridge during the Hornets' 3-2 win at Vicarage Road on Saturday.
Madley, who is the brother of former Premier League referee Bobby, was taking charge of his first Premier League match of the season and Warnock was unhappy that an inexperienced referee was officiating.
The FA said on Sunday that they would wait for the official match report before deciding whether to take action against Warnock and they are now pushing for further detail from the 70-year-old and the club.
Following the game the Cardiff boss said: "I think Troy (Deeney) should have been booked for the challenge on our goalkeeper. If that had been down the other end, there would have been five or six lads surrounding the referee.
"I thought he could have pulled out and the studs went up, but we've got an inexperienced referee, the first game he's had in the Premier League (this season), we've got Andre Marriner stood at the side of me.
"I think it's a disgrace.
"Why should we be an experiment? Is it just because it's Cardiff City? I don't accept that, I think it's poor today. I think an experienced ref would have done something about the challenge."
Watford raced into a 3-0 lead courtesy of goals from Gerard Deulofeu (16), Jose Holebas (52) and Domingos Quina (68).
Cardiff pulled a goal back with 10 minutes remaining through another stunning strike from Junior Hoilett and, two minutes later, Bobby Reid poked home their second.