Vidic facing lay-off until Christmas
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.
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