Crooks was named Super League Young Player of the Year just 12 months ago after a sensational first full season.
He scored 19 tries in just 20 games, was selected in the Dream Team and also appeared in the Challenge Cup final against Wigan Warriors at Wembley.
However, the 21-year-old’s progress has stalled alarmingly in 2014 and he has not played for Hull since June, spending the second half of the season on dual-registration with Doncaster in the Championship.
Crooks had been exposed defensively at times in the top flight but the Airlie Birds know he remains vastly talented and have retained his Super League registration in case he does return.
His father Lee, the former Hull captain and once the sport’s most expensive signing after joining Leeds in 1987, firmly believes he will play for them again.
“Both Ben and myself are pleased the club has agreed to this,” he told The Yorkshire Post.
“These sorts of chances don’t come around that often and once we’d chatted to (Parramatta general manager) Daniel Anderson it became quite apparent it was a massive opportunity for him. It’s a ‘win/win’ for Ben and the club as I’ve no doubt he will come back a lot better player.”
His Hull head coach from last season – Peter Gentle – is now assistant at Parramatta and will help smooth the transition.
Crooks, 51, added: “This year was always going to be difficult for Ben for a number of reasons, including the weight of expectation after how well he’d played last season.
“To be honest, I don’t think he’s played poorly.
“He’s probably just not reached the heights of last season but again there’s reasons – the team has struggled and there’s been a lack of continuity, too, with the players around him.
“That’s not helped but, also, opposition coaches have done a lot more work on him – the same happened to Kallum Watkins and Zak Hardaker early in their career – and he’s had some injuries, too, so it’s been up and down.
“Some of the stuff written in the press about him has been misguided but it has been a frustrating year for him and the club.
“Everyone is confident, though, this will be good for him and Ben’s confidence is fine, too.”
Hull coach Lee Radford is well served for centres having signed Setaimata Sa earlier this season and recruited Australian Steve Michaels for 2015. He already has ex-England star Kirk Yeaman and Joe Arundel, who has been on loan at Bradford Bulls for most of this campaign, and has targeted another NRL player, too.
Crooks will move to Sydney with his partner in November and his father – who played there with Balmain and Western Suburbs in the mid-1980s – said: “It’s the best competition in the world.
“Ben will have to fight tooth and nail to get in their first-grade squad but I’ve every confidence with the tuition of Daniel Anderson, Brad Arthur and Peter Gentle he’ll get an opportunity at some stage. Then it’s up to Ben to take it with both hands.”