Darin Killpartrick is leaving Nyewood Lane after 18 years' service as player, manager and coach.
His last game in the technical area where he has become a permanent fixture over more than a decade will be this Saturday's final game of the season at home to Dartford.
Killpartrick's decision will come as a massive blow to a club where he has led the coaching side of the operation over many years.
He is credited with bringing through a number of young players who have become Rocks regulars and spent eight years alongside Jamie Howell in the management role - first as joint manager and then as head coach.
Rocks manager Jack Pearce described Killpartrick - better known as Dabba - as one of his heroes at the club and said he would be greatly missed and very difficult to replace.
Killpartrick has a young family, is head of the football academy at Chichester College and also coaches the England Colleges FA under-18 team in matches at home and abroad.
We will have an exclusive interview with Killpartrick on this website on Wednesday, and don't miss Thursday's Bognor Observer for the full story and reaction.