Forwards coach Steve Boden will leave Jersey at the end of the season, the Championship club has confirmed.
He has spent four seasons with the Channel Islanders, but is now is set to take up a role with Yorkshire Carnegie.
"We're disappointed to be losing someone who's played an important role for Jersey in recent seasons," Jersey chairman Bill Dempsey said.
"It's less than two months before pre-season, so we want to have a new coach in place as soon as possible."
Boden was under contract until the end of next season, but Jersey have agreed to release him in the summer.
BBC Radio Jersey sports editor Tim Pryor
"Boden was instrumental in Jersey's initial survival in the Championship and his work with the forwards has helped the islanders go on to thrive in the second tier.
"He came to Jersey originally as a hooker but soon switched to the coaching staff.
"The pack is widely regarded as one of the best and most feared in the division, with the driving maul a real weapon for the club in the past couple of seasons.
"He was briefly in charge during the transition from Ben Harvey to Harvey Biljon and has been a reliable right-hand man to both head coaches during his spell at St Peter."