Hull FC's director of rugby Shaun McRae says the club have set a deadline of the end of the week to secure a deal for Castleford stand-off Rangi Chase.
The Black and Whites came close to bringing the 26-year-old in before the transfer deadline last month but
visa issues put paid to the switch.
"We agreed if we couldn't sort anything by the end of the month then we'd let it go," he told BBC Radio Humberside.
"A lot has been going on behind the scenes. It's a complicated issue."
He added: "It's something that has been simmering for quite a long time but it will come to a head very soon."
Chase, last season's Super League Man of Steel, has suffered injury problems and been suspended by the Tigers for his
during this season's campaign.