Castleford have turned down a transfer request from hooker Daryl Clark.
The 19-year-old, who is currently sidelined with a long-term knee injury, made his Super League debut for the Tigers at the start of the last season.
He signed a new five-year contract in October of 2011 and the Tigers have told the player that no offers will be considered for him.
Castleford coach Ian Millward said: "Daryl Clark's agent has put in a formal request that has been rejected unanimously by the board.
"Daryl has a five-year contract with us. We have spoken to parties who were interested in him and they now understand how committed we are to Daryl Clark.
"We are currently in the process of building a team for the future and Daryl is an integral part of that.
"We see no cause to discuss this any further due to our commitment to Daryl and our future planning."
The Tigers are also fighting to keep hold of stand-off Rangi Chase, the reigning Man of Steel who is under contract until the end of 2015 but has found himself in demand.
The club are thought to have rejected an offer from Warrington for the England international and, although Wigan have lost interest, Huddersfield are now thought to be keen to secure his services.