They would have to pay a transfer fee of about £32million to the player's management company, similar to the £18m it cost them to resolve the third-party ownership issues surrounding Mascherano when he moved to Anfield two years ago.
"Yes it's true I see myself more leaving United than staying here," he said. "I don't see why I should lie to people or anything because the fans support me a lot, as you can see. So I don't have any reason to lie to them.
"While I wear the United shirt, I will leave my life on the pitch. My future? I don't know what will happen for my future. I would like to go to Spain, yes, but I don't know yet. I have no preference for a team."
The player's current loan agreement with United ends this summer and it is believed that they are unwilling to make his move permanent.