Forlan, a target for Tottenham, has admitted he is keen on a return to England.
On his time at United, Forlan said of Ferguson: "The way he treated me from the first time I arrived at Manchester was great.
"He was waiting for me in the stadium, took me to the hotel and showed me the facilities at the training ground. I really appreciated that.
"In private he is a very nice person and I have a lot of good memories of Sir Alex. He spent a lot of time with me and he taught me a lot of things."