Vidic sidelined until December
Serbia defender Vidic was ruled out for a minimum of eight weeks after undergoing knee surgery in September.
However, suggestions the 31-year-old could return to action before the end of November appear to have been optimistic, with Ferguson telling MUTV: "I think we're talking around December for Vidic. Maybe around Christmas time."
Vidic missed the final five months of last season with a cruciate ligament problem but this latest setback is not related to that injury.
United have suffered from injuries to defenders this season, with Phil Jones and Chris Smalling also both currently out of action.