Stefano Caira said: "When Francesco was 12 years of age, a representative from AC Milan came with an offer of £150,000.
"The offer had the family in tears and they asked me what they should do. I said Francesco was unlike any other."
He continued: "At 18, Roma made him a professional on £50,000-a-year, while Nike made him a spokesman on £300,000."
Caira revealed their relationship broke down after a mega deal from adidas arrived.
"There was the time when adidas offered him a contract for 1.5 million euros per season and a prize of 500,000 euros per year for life to be an ambassador for adidas. Someone around Francesco said no, and since then the relationship between us has never been the same."