Nicklas, 20, who signs on a dual-registration deal and has made six first team appearances for the Airlie Birds, goes straight in to contention for Sunday’s match against Swinton.
Coach Chris Thorman said: “Danny was coming through the ranks when I was at Hull FC and he is a very talented young player. We have been tracking him all season and now that Hull’s injury concerns have eased somewhat, he is able to spend some time with us which is great news.”
He could line-up alongside another Hull loanee in Chris Green against the Lions, but Thorman will be without Benson who has left the club.
Benson, who joined the club at the start of the 2010 season and was part of the Grand Final winning team of that year, cited personal commitments for his release.
General Manager Ian Wilson said: “Alex has recently started a new business as a personnel trainer and as a result of this, and the fact that his partner is expecting their second child, he feels that he is unable to commit to the demands of professional Rugby League. We would like to thank Alex for his contribution to the club over the past three seasons and he goes with our very best wishes.”
Meanwhile, hooker Brett Turner has signed a contract extension to keep him at the club until the end of the 2013 season.