The United boss said there would be changes made after describing the loss against Leeds as shocking.
It was United’s first FA Cup defeat to a lower league club since they were beaten by Bournemouth in 1984.
Jermaine Beckford got what proved to be the winner when he silenced the United faithful in the 19th minute.
Ferguson said: "We have a semi-final on Wednesday night and a lot of these players won't be playing.
"You have to view that performance in its right light.
"I am shocked by the performance because our preparation for the game was very good. We never got going. The quality of the passing and whole performance was bad.
"Leeds had far bigger appetite than us. We didn't start right, Leeds got their goal and it was something to hold onto."
"The referee gave five minutes," he added. "That is an insult to the game and the players out there."