Rio Ferdinand could be back in action for the Reds in Tuesday's Barclays Premier League clash against Stoke City.
The defender missed last weekend's win at Arsenal after a back problem flared up.
He was on the bench for the FA Cup defeat to Liverpool and Sir Alex hopes he will feature at Old Trafford against the Potters.
"Rio only had one real training session on Friday and we couldn't gamble with only that preparation behind him [for the FA Cup clash], " the boss told MUTV.
"He'll train tomorrow and on Monday and could be ready for Tuesday."
Sir Alex also reportedly told ITV1 before the Anfield cup tie that Wayne Rooney and Nani could be available for next Sunday's league trip to Chelsea, but Phil Jones is likely to be out for a little while longer.
Ticket news: A number of returned match tickets for United vs Stoke City are now available. To book, call 0161 868 8000 or buy online at manutd.com/tickets.