By signing Denmark international Lindegaard from Norwegian club Aalesunds last month, Ferguson has already laid the ground for Van der Sar to vacate the stage next summer.
A further move into the market for Germany keeper Manuel Neuer or Atletico Madrid's David de Gea is also likely with Ferguson admitting that he has learnt from the mistakes he made when replacing Peter Schmeichel in 1999.
"Both of them [Schmeichel and Van der Sar] have been magnificent goalkeepers and I've been very lucky to have had them both." Ferguson said. "I should have signed Van der Sar after Schmeichel. I made a mistake there, but now we think we know where we're going."
United face Sunderland at Old Trafford on Boxing Day two points clear of the pack, with one game in hand on Arsenal and Chelsea and two on neighbours Manchester City.
One of United's 'spare' fixtures is at Chelsea following the postponement of last Sunday's league game because of the adverse weather conditions in the capital.
That game is now unlikely to be rescheduled until March at the earliest, but despite the possibility of the fixture being staged at the end of the season as a possible title decider, Ferguson insists United are happy to play it at any time so long as the new date is 'fair'.
"I'm not concerned when it's played," Ferguson said. "As long as it's fair on both teams, in the sense of congestion of fixtures and wedging it between certain games.
"Obviously Chelsea are in a bad bit of form and they were probably quite happy to get the game off."
Ferguson believes that the demands of European competition could thwart the title chances of City and Tottenham, paving the way for a three-way title battle between United, Chelsea and Arsenal.
He said: "I don't think there will be anyone outside of ourselves, Chelsea or Arsenal. I know Harry is talking up his chances at Tottenham, but they're involved in the Champions League and it's a new thing for them."
Likely lads: goalkeepers who might tempt United
Manchester United are currently scouring the globe to find a successor to Edwin van der Sar, with the following names all under scrutiny.
David De Gea (Atletico Madrid)
De Gea, 20, is Spain's Under-21 keeper. Sir Alex Ferguson watched him in action against Valencia earlier this season.
Manuel Neuer (Schalke 04)
Excelled for Germany at the World Cup. Neuer, 24, has admitted to being interested in move to Old Trafford.
Hugo Lloris (Lyon)
The 23-year-old is established as first choice for France, but Lyon's £25m valuation could scare United away.
Igor Akinfeev (CSKA Moscow)
Russia's number one starred against United in the Champions League group stage last season. Out of contract in Dec 2011.
Maarten Stekelenburg (Ajax)
At 28, he is regarded as well-established and the Holland number one is out of contract in Jun 2012, so he could be signed relatively cheaply.