United want a replacement for Owen Hargreaves, who has barely played in the past two years, and their veteran star Paul Scholes.
The former Portsmouth and Chelsea player is on the way out of Real, and United are ready to pounce.
Will he the Real deal for United? Lassana Diarra (right) could move to Old Trafford
Spanish newspaper AS reports that United are planning to make a £10m bid.
United have looked vulnerable at times, but a decent run has seen them to the top of the Premier League.
And a 2-0 win over Sunderland on Boxing Day kept them two points clear of second placed Manchester City.
Sir Alex Ferguson's men travel to Birmingham on Tuesday night.
Fergie eyes 25-goal haul from red-hot Berbatov as United march onDoubles all round: Berbatov and Tevez on target as Manchester seize the topMANCHESTER UNITED FC