 Heslop was born in York, North Yorkshire, and attended Huntington School.Heslop began his career at Barnsley, where he progressed through the youth team and signed his first professional contract with the club in 2005.After playing regularly for Barnsley's reserve team, Heslop went on loan to Conference National club Kidderminster Harriers at the start of the 2005–06 season, on an initial one-month deal.