Castleford have agreed to a transfer request from long-serving utility player Ryan McGoldrick.
The 31-year-old Australian, who is in his seventh season with the Tigers, was out of contract at the end of the year and had not been offered a new deal.
Castleford coach Ian Millward said: "Ryan approached us out of the blue about leaving.
"Although as a senior player, we'd ideally have him leading us from the front for the rest of the season, with him out of contract we have reluctantly accepted his transfer request.
"With Ryan being a player that has given seven years of service to this club it would be wrong to deny him of this opportunity to continue his Super League career beyond the current season.
"He leaves with our best wishes for the future."
The news comes just a fortnight after promising hooker Daryl Clark had a transfer request rejected and a little over a week since the club suspended stand-off Rangi Chase pending the outcome of an internal investigation into an alleged breach of discipline.
McGoldrick, a United States international who helped the Tomahawks qualify for the 2013 World Cup, is expected to join a new club immediately.
He said: "Castleford Tigers has been a major part of my life for the last seven years and a main part of my playing career.
"In an ideal world I'd have liked this to continue for years to come but this isn't always possible and in 2013 we are moving in different directions.
"An opportunity has arisen which may help me continue my Super League career into the future and I have chosen to take it.
"I want to thank all of the fans for the last seven years and the club, staff and players that have made my time here thoroughly enjoyable.
"I wish everyone involved with the club all the best not only for the rest of the season but for years to come."
McGoldrick has been linked with a move to Hull, from where Castleford completed the signing of scrum-half Jamie Ellis.
The 24-year-old Ellis was due to join the Tigers on a two-year deal from next season but he was released from his contract by Hull yesterday and, after bringing forward his move, is set to make his debut against Huddersfield on Sunday.
Millward said: "Ryan's departure enables Jamie Ellis to come in early. We have struggled with our kicking game this year and Jamie gives us a quality kicking game.
"He's been playing regular Super League but not long minutes. This gives him a chance to get longer minutes which will benefit us in the long term.
"Jamie is a talented English half-back if, given time and patience, can make his mark in Super League in coming seasons."
