The FA has sought written observations from Liverpool boss Jurgen Klopp after his comments concerning the referee in his side’s draw at West Ham on Monday.
Klopp admitted James Milner was offside in the build-up to Sadio Mane’s goal and felt that mistake influenced later decisions made by referee Kevin Friend.
“I heard our goal was offside, I’m pretty sure the ref knew that,” the German manager told BBC Sport.
“In 50-50 situations it was always a free-kick for the other team.”
Speaking to Sky Sports, Klopp added: “As a human being, if I know I have made a big mistake in the first half, I don’t want to open the gap any more.
“Referees are obviously human beings, and I understand that, but I didn’t during the game because I had no clue that our goal was offside.”