Ferguson has until Friday to offer the Football Association an insight into his comments, which followed Manchester United's 2-2 draw with Sunderland at Old Trafford 10 days ago.
The Manchester United manager was fuming with Wiley's handling of the match and made a series of statements about Wiley's fitness, including a belief that he took longer than necessary to book players because he "needed a rest".
The United chief has already offered a public apology and has stated he never meant to personalise what he feels is a valid topic for debate.
That was not enough for referees' chief Alan Leighton, who has called for a UEFA-style touchline ban which would prevent Ferguson having any contact with his team during a match.
For Megson, this is just another example of someone grabbing cheap publicity at Ferguson's expense. "Fergie couldn't have done any more," the Bolton boss told the Manchester Evening News. "He gets hung out to dry because of who he is. He has apologised and then everyone criticised the apology.
"Alan Leighton seems to have a bee in his bonnet about the apology. I have seen him quoted as saying it is half-hearted. But you are damned if you don't apologise and damned if you do. What is he supposed to do? He has said something and then, having had time to think about it, he has said 'sorry'. End of story - move on."
Ferguson is due to return from a short break in New York on Wednesday and will be back behind his desk in the morning to consider his response, which needs to be with FA officials on Friday.