Wolves boss Nuno Espirito Santo has been asked by the Football Association to explain his comments criticising referee Lee Mason, reports BBC Sport.
Nuno said after Wolves' 2-1 defeat at Burnley that Mason "is not good enough" to officiate at the top level.
The Portuguese manager queried the way in which Mason "handles" players, adding that he "worsens the flow of the game".
The FA will decide whether to act once it has received Nuno's observations.
Under current FA regulations, post-match comments that criticise the performance or competence of a match official are permitted unless they imply bias, attack the official's integrity, are personally offensive, are prolonged, or are particularly unreasonable.
