Ferguson is expected to ring the changes for the fifth round tie at Old Trafford against a Reading side that has lost just one of their last seven games.
Captain Nemanja Vidic, who was a surprise omission from Ferguson's starting line-up against Real Madrid in the UEFA Champions League, should return at the back as United look to secure a quarter-final place.
Veteran midfielder Paul Scholes is out for two weeks with a knee injury but Tom Cleverley and Anderson could both face Brian McDermott's men. Other changes may include the return of Javier Hernandez up front with Nani and Ashley Young on the wings.
"Reading are a team who are showing plenty of fighting qualities, as you would expect given they are down near the bottom," said Ferguson.
"We'll take nothing for granted. In the FA Cup you always expect the unexpected. You just hope you're not a casualty or a shock.
"I will make some changes but I don't think the incentive to get to the quarter-final is lost on any of the players.
"There is a good spirit and they're all contributing. Whatever side I pick we're expected to qualify."