Hull KR forward Tyrone McCarthy has agreed a two-year deal with Australian NRL side St George Illawarra Dragons.
Ireland international McCarthy, 27, captained Hull KR in the Challenge Cup final at Wembley last month as his side were beaten 50-0 by Leeds Rhinos.
He has been with the Robins for one season after joining from Queensland Cup club Northern Pride and will return to Australia at the end of the season.
"It's been a tough decision to make," McCarthy told the Hull KR website.
"Captaining such a proud and historic club like Hull KR in the Challenge Cup final was one of the highlights of my career so far, despite the result, and I would have been very happy to stay.
"But it's always been one of my ambitions to play in the NRL and this was an opportunity I couldn't turn down."
Meanwhile, half-back Albert Kelly is set to miss the rest of the season to recover from a knee ligament injury.
Kelly has played just two of their last seven games - the Challenge Cup semi-final against Warrington and the Wembley final.
The 24-year-old was rested for Sunday's 20-18 win against Wakefield in The Qualifiers, a victory that practically secures their Super League status.
"We will probably put him away until pre-season," said boss Chris Chester.
"It was a 12-week injury and he has come back after five weeks but it's not fully healed yet," he told BBC Radio Humberside.
"We have to be very careful with his knee as it just takes one awkward tackle and he's out for six to nine months."
Hull KR, who have three matches of the season left, are top of The Qualifiers table as they aim for a top-three finish to guarantee their Super League place for the 2016 season.