McLeish admits that it can be very difficult to avoid conceding fouls against "clever" players, but he will be urging his team to avoid giving away soft free kicks and penalties.
"We will try to stay on our feet against all of United's players," he said. "But sometimes it's not as simple as that. Ashley is a quality player. He is renowned for his assists, but players have become clever.
"Sometimes the slightest touch can be enough for them to go down. I don't envy the referees. I don't want to see a blatant dive but it is very difficult for referees to see if there has been genuine contact."
Villa are currently 16th in the Fair Play League table.