Argentine midfielder Mascherano maintains that he does not understand why he was sent off in his side's 3-0 defeat by Manchester United.

Hackett is the general manager of the Professional Game Match Officials Limited, and in charge of the appointment and assessment of Premier League referees.

Mascherano - who had already been booked - appeared to question referee Steve Bennett's decision to caution Fernando Torres, and was then shown a second yellow card himself.

The FA will review Bennett's report and look at video footage before making a decision as to whether to increase Mascherano's punishment.

A decision is expected later on Wednesday.

The 23-year-old's case will not be helped by his furious reaction to his dismissal and his refusal to leave the pitch before he was dragged away by team-mates and management.

Mascherano is suspended from Sunday's Merseyside derby at Anfield but a charge of improper conduct would mean he also missed subsequent Premier League games against Arsenal and Blackburn.

But if Mascherano's punishment is increased, Liverpool would almost certainly demand a personal hearing, which would delay any future ban.