Hull FC have released half-back Jamie Ellis with immediate effect.
The 22-year-old moved to the KC Stadium on a two-year contract at the start of the season but, after failing to establish himself in Peter Gentle's starting XIII, he was given permission to speak to other clubs.
Ellis signed a two-year deal with Super League rivals Castleford Tigers last month that is due to take effect in 2013.
Despite his premature release, Ellis's move to Castleford is not expected to be brought forward.
Instead, it is believed that he will join a Championship outfit on a short-term basis.
"We thank Jamie for his contribution this season and wish him well for the future," said Hull director of rugby Shaun McRae.
Hull are currently seventh in the Super League table.
