Manchester United manager Jose Mourinho has been contacted by the Football Association after saying it would be “difficult” for Anthony Taylor to referee Monday’s game at Liverpool.
Mourinho said appointing Taylor for the game had put “pressure” on the Manchester-based official.
Managers are not supposed to speak about referees prior to matches.
The Portuguese, 53, has until Friday to offer a response, which will then be considered by the FA.
Monday’s game finished 0-0.
Former referee Howard Webb told BBC Radio 5 live that Mourinho should be “taken to task” by the FA.
“It’s one thing someone from Manchester or Liverpool taking to social media, a fan commenting, but for a coach to do this when he knows the rules then there should be some action taken against him,” added Webb.
“Focusing the attention on a referee is simply mind games and trying to gain an advantage.”