Bradford Bulls have been rocked by a transfer request from back-row forward Elliott Whitehead.
The 23-year-old, who is yet to miss a game this season, will not play in Sunday's clash with St Helens after telling coach Francis Cummins he wants to play for a bigger club.
Cummins said: "His agent, Andy Clarke, rang me last Friday and told me that Elliott wanted to leave because he didn't feel the progress of the club was what it should be and that he wanted to test himself at a top-four club.
"I kept it professional and decided he would play at Hull KR last Sunday and I then sat down with Elliott first thing on Monday morning.
"Elliott again reiterated what his agent had said. I asked him if there anything else I or the club could have done better and he answered 'no'.
"He is now on leave until the situation is resolved. I can't have players in my squad who don't want to be here."
Whitehead, who made his Super League debut in 2009, is under contract at Bradford until the end of 2016, with Catalan Dragons and Salford reportedly keen on his services.