Nick Fozzard has resigned from his post as Commercial Manager at Castleford.
His wife Sarah has also resigned from her post as Marketing Manager.
Interim CEO Steve Gill said: "It is with disappointment that we confirm the departures of Sarah and Nick from the club. I’d like to take this opportunity to thank them both for their efforts.
"The Membership scheme has been a fantastic introduction to the club and Sarah played no small part in its delivery. We wish her well.
"Nick’s transition from player to commercial manager was amazing to see. We hope that his next venture in life is prosperous and one that gives him fulfilment.
"The aim of all remaining staff is to roll our sleeves up and ensure the backroom team are in a position to make the most of the positive start to the season made by the players and coaching staff."
The resignations follow on from last week's departure of chief executive Steve Ferres.
Hull Kingston Rovers have confirmed that experienced halfback Terry Campese has joined them pn a one-year deal ahead of the 2015 campaign.
Leigh Centurions have confirmed that Fiufui Moimoi has signed a one-year deal with the club, with the option of a second year.
The UK Parliamentary Rugby League Group has given its backing to a fans' boycott of the BBC's annual Sports Personality of the Year award.
The RFL have confirmed that there will be four rule changes at all levels of the professional game for the 2015 season.