The Daily Mail says Sir Alex Ferguson has already earmarked the 19-year-old England defender as the man to succeed Gary Neville at Old Trafford.
Ferguson thought his chances of landing the player in the short-term had been scuppered when Richards signed a new contract at Eastlands earlier this year.
But uncertainty over Sven Goran Eriksson's future and owner Thaksin Shinawatra's unwillingness to invest heavily or sort out contract issues with other players has unsettled the defender.
City now appear ready to cash in on their most prized asset. If United are willing to offer in the region of £20 million then Shinawatra could cash in.