Van der Sar has been absent since mid-November due to a knee injury and personal issues as his wife suffered a stroke shortly before Christmas.
However, Van der Sar returned to training with the club at their training camp in Qatar last week after his wife made a complete recovery, and Ferguson believes the 39-year-old could provide a major boost for a defence that has suffered from numerous enforced changes and poor form in recent weeks.
"Edwin has come back to training and has done very well," he said. "He has been out for a few weeks and it is great to see him back. He will give us so much experience when he eventually does come back, which is important to us. It depends how Edwin feels but he has been training very well."
Tomasz Kuszczak has been deputising for Van der Sar.
Meanwhile, Ferguson has revealed Dimitar Berbatov is reluctant to undergo an exploratory operation on his knee injury as it is hoped it can be delayed until the summer.
"Dimitar doesn't want an operation," he said. "Sometimes he feels the injury, other times he doesn't. It might have been the warmer climes but he didn't feel it at all in Qatar last week. We are just keeping an eye on it at present."
Ferguson also confirmed long-term absentees Rio Ferdinand and Owen Hargreaves continued to make progress at the training camp.
"They both took part in some work and Rio in particular is not too far away now,'' he said.