FORMER Carlton coach Brett Ratten will be Alan Richardson's right-hand man at St Kilda from next season in a reversal of their roles at the Blues back in the day.

Ratten, who coached Carlton from 2007 to 2012, spent the past six seasons as an Hawthorn assistant under four-time premiership coach Alastair Clarkson after Carlton sacked him. 

The 47-year-old will remain with the Hawks until their finals campaign ends.

Ratten was quickly linked with a move to the Saints after Hawthorn announced on August 2 that he would "explore new opportunities" and he met with them in mid-August. 

Ratten will be part of a new coaching crew at St Kilda, with Brendon Lade departing Port Adelaide to also join the Saints' cause. 

Senior coach-in-waiting Adam Kingsley elected to switch clubs to Richmond, while Simon McPhee, Rohan Welsh and Lindsay Gilbee did not receive new contracts. 

St Kilda football boss Simon Lethlean said Ratten's experience would be vital as the Saints seek to rebound from an underwhelming 2018 season.

"Brett is one of the most experienced assistant coaches in the game and we look forward to the impact he can have on our football program," Lethlean said.

"He is highly regarded across the football industry, and as midfield coach at the Hawks, was a key driver in their premiership success. 

"We respect that Brett's focus is rightfully still on his current role at Hawthorn, however, we look forward to welcoming him and his family to the Saints over the off-season."