Sharp, 21, scored 56 goals in under 100 appearances after the Blades sold him to the Irons, and had been coveted by several Championship sides. It was the lure of his hometown club, however, that proved strongest for the youngster.
Jonathan Forte was included as a makeweight in the deal, which was completed for an undisclosed fee of which 25% will be returned to Bramhall Lane as part of their sell-on clause.