Despite a ninth successive clean sheet in Wednesday night's 1-0 Premier League win over Wigan at Old Trafford, Ferguson is already without defenders Rio Ferdinand and Patrice Evra and could now be missing Jonny Evans at the Reebok after he suffered an injury against the Latics.
The United boss was quick to praise Vidic, his only remaining specialist centre-half, following the Wigan win and said: "Nemanja was magnificent. It was the best performance you are likely to see from a natural centre-half."
He added: "His reading of the game is excellent and he is as tough as nails. He was absolutely superb."
The same could also be said of Wayne Rooney, although the England striker was only on the pitch for six minutes.
It was long enough to do Wigan enough damage to consign them to only a second defeat in eight games though as he tapped home Cristiano Ronaldo's first-minute cross.
"Wayne scored a good goal but he will be out for about three weeks now. Hopefully it is no longer," said Ferguson.
Wigan boss Steve Bruce also has doubts over his personnel for Saturday's encounter with Manchester City at Eastlands.
However, Bruce's fears concern the sale of Honduran midfielder Wilson Palacios, who was the subject of a £10million bid from Tottenham that was instantly rejected.
Bruce said: "In two years' time Wilson will be as good a midfielder as there is. We will have to see what develops in the next 24 or 48 hours and what Tottenham are prepared to go to."