Manchester United goalkeeper Edwin van der Sar has been sent home to the Netherlands to have a second opinion on the knee injury that has kept him sidelined for a month.
United had hoped that the injury would prove a short term one but with Van der Sar still struggling, Ferguson has granted the player permission to be examined by his national side.
"Edwin is going back to Holland," said Ferguson. "It is a change of scenery for him and the Holland team doctor will have a look at the injury.
"He has never had an injury like this in his life before so we think it is a good idea and expect him back in a couple of days."
United have been hit by a succession of injuries of late and Ferguson is still unsure as to whether Nemanja Vidic will face Fulham at the weekend. The Serbian was substituted during Tuesday's 3-0 win over Wolves with a calf strain.
"We're waiting on Nemanja Vidic," Ferguson said. "Hopefully he'll be okay for tomorrow but he needs to train today."
Gary Neville and Rafael are nearing a return and could face Hull on December 27 but Nani will be absent for two weeks as a result of an ankle injury.
Ferguson described long-term injury victim Rio Ferdinand as being "a lot better" and hinted that the England international could return within three weeks. Owen Hargreaves will also be hoping to return to action at the end of January.