Ferguson has confirmed he has spoken to the winger about the situation.
"I have had a word with Ashley," said Ferguson. "He understands where we are coming from. Hopefully it makes a difference."
After watching this week's Champions League semi-finals, Ferguson feels we are in an era where anything goes.
"Last week, if the player doesn't bring Ashley down he is going to score," said Ferguson. "It was a clear goalscoring opportunity.
"He caught him and he did overdo the attempt to get a penalty. I am not sure he tried to get the penalty but he certainly went down quickly.
"But people have reacted because it is Manchester United.
"Then you see the other night in the Chelsea game, we are in an age where you expect it now."