Castleford winger Josh Griffin has left the club to switch codes with Leeds Carnegie.
Griffin, 22, has scored 12 tries in his first season at the Tigers, since arriving from Huddersfield in the winter.
He is reported to have already began training with union side Carnegie, who share Headingley with current Super League champions Leeds.
It promises to be a close season of much change for Castleford, with coach Ian Millward already having made six new signings for 2013.
Currently sitting on level points with London and Widnes at the bottom of the table, the Tigers are likely to lose 2011 Man of Steel Rangi Chase at the end of the season.