The Reds are waiting for their 39-year-old Dutch keeper to come to them with an answer to their offer.
In past years Van der Sar has always agreed his new extension in December, but this campaign his future plans were thrown into confusion when his wife suffered a brain haemorrhage just before Christmas.
She is making a good recovery in Holland but it has understandably put the keeper's plans on the back-burner.
That and the fact he turns 40 in October have made it a big decision for Van der Sar.
"I have given loads of thought to whether I will continue," he said.
But the final decision has yet to be made and United are happy to wait for him to make up his mind.
However, it is unlikely to impact on United's search for new goalkeepers with dossiers already in place on several contenders.
United also have to consider the futures of their other senior keepers Tomasz Kuszczak and Ben Foster.
Foster's World Cup place is in jeopardy. He has not played for United's first team since the end of November in the 1-0 Champions League defeat against Besiktas and messed up his chance of ousting Van der Sar at the start of the season when he failed to impress in 11 games.
Manuel Neuer (Schalke), Igor Akinfeev (CSKA), Rene Adler (Bayer Leverkusen) and Hugo Lloris (Lyon) have all been linked with a move to the Reds.
Meanwhile, United are watchiing Benfica's Brazilian defender David Luiz, according to the Daily Mail.
Which goalkeeper would you like to see United buy? Have your say.
Source: Manchester Evening News