The two clubs will face off in Manchester on Thursday for the first leg of the Europa League semi-finals.
Speaking before the game, Ferguson told Gazzetta dello Sport: "We liked the player and we would have liked to include him in our plans, but when we expressed our interest, it immediately became clear that Totti didn't want to leave Rome.
"He was deeply attached to his city. His CV is clear. Totti has, in his career, only worn the Roma shirt."