The Maidstone-born midfielder spent three seasons at Bristol City prior to joining the Gills in July 2016.
Wagstaff made 90 appearances for the Robins, nearly a third of which came in City’s League One-winning 2014/15 campaign. He also scored their final goal in a 3-1 victory against the Gills at the MEMS Priestfield Stadium in December 2014.
His last goal for City game in their 6-0 victory over Bolton Wanderers at Ashton Gate in March 2016.
Educated in Royal Tunbridge Wells, Wagstaff joined Charlton Athletic’s Academy aged eight, and went on to captain their Under-18 squad.
He made his professional debut for the south London club in April 2008, and went on to make 70 league starts for the Addicks, including 40 in their promotion-winning 2012/13 season. He also played alongside current Gills team-mate Josh Wright for the Addicks.
Wagstaff had loan spells at AFC Bournemouth (August to September 2008), Northwich Victoria (November to December 2008) and Leyton Orient (October to November 2012) during his time at The Valley.