Hull FC forward Lee Radford has retired from playing to take over as assistant to new boss Peter Gentle.
The 32-year-old, who was halfway through a two-year playing deal, has signed a three-year coaching contract, which includes running the Under-20s.
He has experience of coaching with amateur side East Hull.
"This opportunity wouldn't necessarily have been there in 12 months' time and that made my decision pretty straightforward," said Radford.
"I've had a fantastic 18-year playing career, racking up nearly 400 games since my debut when I was a skinny 16-year-old and I've been fortunate to pick up plenty of silverware along the way.
"I'm really looking forward to working with Peter and I certainly think we have exciting times just around the corner and that is something I want to be part of."
Radford started his career with Hull before moving to Bradford, where he won Challenge Cup and Super League Grand Final titles, before rejoining his home town club in 2006.
Hull's new director of rugby Shaun McRae told BBC Radio Humberside: "Clearly I had in mind to offer him a role on the coaching staff but in no way shape or form did I say to him that 'you must retire'.
"If he wanted to play in 2012 then he was able to play. There was no pressure to retire but to go on the coaching staff he had to retire.
"There was an opportunity here and that opportunity probably wouldn't be here at this club in 12 months' time as I'm going to have to employ somebody.
"It's a really big job for him and it's a pathway as well.
"He's going to be involved with some good people and he's going to be involved with a very good club, which he's represented with great distinction for a long period of time.
"He's a Hull person and I think it's important to have someone like that in your organisation."