Ferdinand was shown on camera striking Fagan with his arm during United's 4-0 victory over Hull on Saturday. He was not punished at the time but has now been handed a three-game suspension for the action. And, having denied the charge, The FA has extended the ban by an additional game.
An FA statement read: "At an Independent Regulatory Commission today, Manchester United defender Rio Ferdinand was given a four-match suspension to be served with immediate effect.
"Ferdinand denied a charge of violent conduct in relation to an incident in Manchester United's home match with Hull City on Saturday 23 January 2010.
"Furthermore, the Independent Commission felt that the player's denial of the charge was frivolous and on that basis have awarded an additional one-match ban upon the statutory three-match ban awarded for violent conduct. "
Sir Alex Ferguson had earlier vowed to fight the charge. He said: "If it's a fair hearing then he (Ferdinand) has a good chance. He was wrestled and punched, all sorts of things happened to him, and he was just trying to wrestle free from it.
"Unfortunately for us, he's caught him [Fagan] on the back of the head. But we will contest it."