Vidic sustained a calf strain during the 3-0 win over Wolves at Old Trafford on Tuesday night after getting himself on the score sheet with United’s second goal.
The defender joins Wes Brown on the treatment table, he is out of action over the Christmas period after picking up a hamstring injury against Aston Villa at the weekend.
This means Michael Carrick will continue in defence as will youngster Ritchie De Laet.
"Ritchie showed some promise and he will probably be there on Saturday," said Sir.
"We just have to get on with it."