Hull FC have signed Bradford Bulls club captain Andy Lynch on a two-year deal for a "significant" six-figure fee.
The 31-year-old England prop moves on after spending six years at Odsal.
But Hull have released ex-Great Britain centre Martin Gleeson and opted not to give forward Mike Burnett a new deal.
And the club have vowed to undertake a review of their entire youth structure after losing promising academy player Luke Briscoe, younger brother of England international Tom, to Leeds.
Briscoe, who joined the club as a 15-year-old and has impressed in the Under-18s and Under-20s, was offered a new contract but Leeds - run by Gary Hetherington, husband of former Hull chairman Kath - have proved too big a lure.
"The club is extremely disappointed to announce that Luke Briscoe is leaving Hull FC to join Leeds Rhinos," said chief executive James Rule. "The entire youth and academy structure will undergo a full review with the clear objective of preventing this ever happening again."
Rule also confirmed the exit of Gleeson, 31, who joined Hull on an 18-month deal in April after his release by Wigan.
He has played only seven games, having been on sick leave since June due to a stress-related illness.
"Hull FC have terminated the contract of Martin Gleeson," said Rule. "We thank him for his contribution to the club and wish him the best of luck in the future."
Lynch is Hull FC's sixth signing ahead of the 2012 season, following Leigh scrum-half Jamie Ellis, Wigan prop Eamon O'Carroll and their trio from Down Under, all confirmed in June, long before the announcement of coach Richard Agar's departure, Wests Tigers full-back Wade McKinnon and New Zealand Warriors duo Aaron Heremaia and Brett Seymour.
With the appointment of new coach Peter Gentle and the return of Shaun McRae as director of rugby, Lynch predicts: "There are exciting times ahead at Hull.
"Hopefully we can challenge for some silverware within a couple of years.
"Look at the signings they've made. They've recruited early and got ahead of the game and they'll have a good squad next year.
"It will be a tough move to leave Bradford. I have been there for a long time and have some great memories but, at the same time, it is a move I am relishing and looking forward too.
"It was probably the right time for a change for me. It's just the next chapter in my career."
Black and Whites director of rugby Shaun McRae said: "We are delighted to be able to bring a player of his undoubted calibre and experience to our club, who will have an effect on and off the field, as well as adding some real value to a now blossoming front row.
"Andy is a terrific professional and a player who has been at the top of his game throughout his career.
"He can look back on his time at Bradford as a very proud man where he has led from the front as captain and claimed numerous awards for his consistently high standard of performances."