A transfer directly between Manchester United and Liverpool would be extremely controversial.
Phil Chisnall was the last player to cross the divide between the bitter rivals when the Manchester native joined Liverpool in 1964.
Gabriel Heinze almost joined Liverpool from United in 2007, but Alex Ferguson blocked the move and the Argentine attempted to push the transfer through. Heinze had to settle for signing for Real Madrid.
The chances of a player moving directly between the clubs appears remote, but Memphis Depay's odds on joining Liverpool have shortened in recent days.
The Dutch winger, who failed to impress during his debut season at Old Trafford, has moved from 7/2 to 7/4 to move to Merseyside.
Ladbrokes News’ Dave Burin said: "Man United fans will have a new Public Enemy No. 1 if their big-money buy swaps the Stretford End for the Kop this summer."
Memphis Depay – Next Club by end of Summer Transfer Window:
Liverpool - 7/4
Leicester City - 10/1
Stoke City - 10/1
PSV Eindhoven - 10/1
Arsenal - 14/1
Borussia Dortmund - 16/1
Chelsea - 16/1
Manchester City - 20/1
