The young defender has been the subject of a rejected £20m bid from Chelsea, who are expected to return with an improved offer.
Jose Mourinho has gone public with Chelsea's interest in the 20-year-old centre back, a move which is understood to have infuriated Everton.
It's now emerged that United are also interested in Stones having identified his potential three years ago.
Louis van Gaal has been desperately seeking to bolster his defence with interest in Sergio Ramos and Nicolas Otamendi ongoing.
United could find themselves in a strong position to recruit Stones. The club would be willing to let Jonny Evans move in the other direction having told the Northern Ireland defender he can go once they add to their back line.
Other players could also be used as bargaining chips, including Ashley Young and Javier Hernandez.Reuse content