The 21-year-old has since gone on to impress for the Serie A outfit, which has resulted in criticism being aimed at United for allowing him to depart.
However, Gill has claimed that he and the club could have done no more to tempt the midfielder into remaining at Old Trafford.
"We offered Pogba a very good wage, as well as a very generous fee for his agent. I don't want to go into details, because it was a complex issue. However, what I can say is that we were very disappointed," Gill told RedCafe.
"Whenever a player is determined to leave and his contract allows it there is nothing we can do about it. I can assure you that we did not hold anything back, financially."
Pogba made a total of seven senior appearances for the Red Devils.