The last player to transfer from Manchester United to Liverpool was Phil Chisnall back in 1964, but Rafa intends to change that apparently.
According to The Times:
The Argentinian, who is playing for his country in the Copa America, was thought to be close to moving to a club in Spain, but Liverpool are understood to have made preliminary inquiries about his availability.
Potential suitors may not be required to negotiate directly with United as the 29-year-old can be bought out of his contract for approximately £6 million under new Fifa regulations.