Amad signed from Atalanta, though didn't join United until January.
Transfer expert Fabrizio Romano told the story in short on his Twitter page and said: "I still remember this day, October 5. Amad Diallo was one step away from joining Parma on loan, then Manchester United appeared and signed him on a permanent deal.
"Amad was buzzing like a child: 'Man Utd, I'm dreaming...'. His journey has only just started."
"We worked according to the dictates of the new club, we tried to buy many young players who will be able to give us a hand," Lucarelli told Sky Italia.
"We already had a proven squad, which is strengthened by many interesting young players. You must ask Atalanta about Amad, we had the agreement and then the negotiation with Manchester United started and they sold him."