The Germany World Cup is new United manager Louis van Gaal's No1 defensive transfer target.
Sport says Barcelona were also keen, but have been informed by their intermediaries that pursuing a deal would be a waste of time as Hummels wants to join United.
Hummels was given his first team debut by Van Gaal at Bayern Munich and is keen on a reunion.
The defender refused to rule out a move to United during the World Cup.
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