Fergie is hoping to regain the services of skipper Nemanja Vidic, Tom Cleverley as well as Chris Smalling for the clash at Anfield on October 15th.
"The most important thing is the work they do before the internationals finish," Ferguson told MUTV.
"We really want to have Vidic and Cleverley doing some really strong work, and Smalling too, that would bring them on to a level that they could play at Anfield.
"You can't go there with players who are semi-fit or just coming back from injury. You need players who are fully focused and up to speed in terms of fitness and sharpness."