King is considered one of the most promising young clipboard holders in the game. The former NSW and Australian centre has been assisting Michael Maguire after working his way up from South Sydney's lower grades. However, a vacancy appeared at Bondi Junction after Roosters assistant Steve McNamara left to take up the role under new Warriors coach Stephen Kearney.

Souths had already drastically overhauled their coaching structure after parting company with assistants Kurt Wrigley and Wayne Collins. Former Canberra head coach David Furner, an assistant at the Cowboys, has stepped into the breach, while Parramatta's head of high performance, Paul Devlin, has also joined the cardinal and myrtle.

However, they now have another role to fill after King's shock resignation. The Rabbitohs have made a slew of off-field changes after their disappointing 2016 season, while Maguire comes off contract next year. Maguire has been under pressure after missing the finals, but Rabbitohs officials are likely to offer the premiership-winning coach an extension.

King has a long association with the Rabbitohs, having played 23 games for the club before retiring in 2013. The 36 year old continues a trend of talent switching from Souths to the Roosters, including CEO John Lee, pivot Luke Keary and forward Paul Carter. A number of promising Souths juniors - including Nat and Egan Butcher, Paul Momirovski and Grant Garvey - have also transferred to the Tricolours.

Meanwhile, Parramatta have signed Penrith utility Will Smith on a one-year deal.

The Eels have been aggressively signing and re-signing key players throughout the offseason, with Smith the latest to put pen to paper.

Smith has made 21 first-grade appearances for the Panthers since making his NRL debut in 2014 and is hoping to add to that tally at Penrith's western rivals. The 24 year old has is one of the game's most versatile players, having played in the halves, centres and fullback during his stint at the foot of the mountains.

Eels coach Brad Arthur is likely to opt for Clint Gutherson as the man to partner Corey Norman in the halves in 2017, although Smith and Josh Hoffman may get a chance to stake their claims during the preseason.

Smith's future was clouded after suffering a serious knee injury at the end of last season. However, he is expected to recover in time to push for selection for the Auckland Nines.

In other signing news, the Roosters have signed Parramatta back-up half Mitchell Cornish.