Rio's season over, but not career
Tommy's Top 25: Where do United rank?
Ferdinand's ongoing absence is part of an alarming injury crisis for Treble-chasing United, with manager Ferguson admitting "it has all fallen apart in the last week".
The England captain has been out with a calf injury since February 5 and Ferguson revealed he is no closer to returning to training and that it would be "lucky" if he featured again this campaign. But it is just the latest of a long series of setbacks for Ferdinand, raising questions as the whether the 32-year-old can continue at the top level.
This is a third consecutive injury-blighted season for Ferdinand, whose fitness woes started with a back injury aggravated during the 2008 World Club Cup in Japan, which has triggered a list of muscular ailments that have sidelined him for lengthy periods. Given his age, it would be tempting to start writing Ferdinand off as a major force, though Ferguson feels such a stance would be premature.
"Rio has plenty of years ahead of him,'' Ferguson said. "He has had a few injuries over the last few years I am sure that are a concern for him. But he is still capable of coming back and playing at the top level. He only needs the example of Gary Neville. I am sure he sees that. He is desperate to get back and he will.''
If he fails to fully recover, Ferdinand would not be the first 32-year-old to find his body was incapable of meeting the demands of English football, while the latest situation has put him on the brink of losing the England captaincy.
"I am not getting involved with that,'' said Ferguson. "Calf injuries can be troublesome. I remember Bryan Robson was out for four months with a calf injury. It is looking that way again with Rio. We are not looking at it as a short-term situation for us. He has been out for a few weeks now anyway and has not started training yet. It looks to me as if we will be lucky to get him back for some point of the season.''
England coach Fabio Capello has suggested that the hamstring and calf problems are all related to a back condition Ferdinand has admitted trying to hide from Ferguson until he was called to account for a particularly poor performance against Liverpool at Anfield last season.
On that occasion, Ferdinand was ruled out for three months and has since not wasted an opportunity to state how fit he was, even though there were signs - standing up for the duration of a flight to Valencia in September - that a problem still existed.
In ruling John O'Shea out for five weeks with the hamstring injury he sustained in Tuesday's Champions League win over Marseille, Rafael for two with a similar problem and skipper Nemanja Vidic for at least another week with a calf injury, Ferguson has laid bare a defensive crisis with echoes of last season.
Then United managed to get through a Champions League trip to Wolfsburg but hit a brick wall at Fulham, when Michael Carrick and Darren Fletcher played in defence alongside Ritchie de Laet, who is currently on loan at Portsmouth. The subsequent defeat proved costly as United finished a point behind Chelsea in the title race.
"We hope a similar thing doesn't happen,'' Ferguson said. "We hope it is just a bad spell. Apart from this period, we have been OK. It has all just fallen apart in the last week.''
The chinks of light come in the form of a return to fitness of Northern Ireland international Jonny Evans, who replaced Ferdinand in that Wolves game but has not played since after picking up an ankle injury in training.
Ferguson has admitted it would be a risk to push Evans into battle, although with Fabio, Chris Smalling, Wes Brown and Patrice Evra - recalled by France on Thursday for the first time since his involvement in the World Cup scandal - as his only fit defenders, he may have no other option.
At least Smalling has stood up to the exceptional demands being placed on a 21-year-old, who only three years ago was plying his trade in the non-league with Maidstone United.
"Chris has been fantastic,'' Ferguson gushed. "Every game he has played recently has been massive and he has been brilliant in them all. Confidence plays a part, as it would with any young player. But everyone has recognised his level of performance.''