Schweinsteiger, 24, has the kind of experience and top-class pedigree that United will need if they lose Ronaldo to his "dream club," and contact has already been made at the highest level.
The powerful German is in the last year of his contract with Bayern and looks sure to quit despite the pleas of new coach Jurgen Klinsmann.
Schweinsteiger, who was also on Chelsea's radar under Avram Grant's management and is still interesting the Londoners, would be able to move relatively cheaply.
Sources in Schweinsteiger's camp say there has been contact with United, who will set the wheels in motion if Ronaldo waves goodbye to Old Trafford.
