The Dutch keeper has in recent seasons made a decision about his future at Christmas and, while the 40-year-old has yet to confirm anything himself his time, Sir Alex is already preparing for life without him.
"We’re planning for it to be possibly Edwin’s last season," the Reds boss told his pre-Sunderland press conference on Thursday.
When asked whether Edwin would go into coaching after ending his playing career, Sir Alex said: "He’ll be someone of interest in terms of his knowledge and experience, but we haven’t discussed that yet."
New signing Anders Lindegaard has begun training with the Reds and will be officially registered with the club in the New Year.
Edwin is likely to be between the sticks on Sunday against the Black Cats, a game Ferguson is not taking lightly, especially given a virus has swept through his camp again.
United have no new injuries to report for the Boxing Day encounter, with Paul Scholes (groin) and John O'Shea (calf) still sidelined. However, Nemanja Vidic, Nani, Anderson and Michael Carrick have all been laid low with a bug in recent days.
Ferguson is optimistic that quartet will be fit for Sunday but admits the postponement of last weekend's trip to Chelsea may have been a blessing in disguise in one regard.
"We've no injuries to report other than Scholesy and O’Shea," he continued. "Wes Brown picked up a little injury in the week but he should be OK.