IT'S OFFICIAL. After months of speculation, Tom De Koning has told Carlton he will be joining St Kilda as a restricted free agent.

The 26-year-old is poised to sign a massive long-term deal with the Saints reportedly worth around $1.7 million over eight seasons, one the Blues say they are "not prepared to match".

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De Koning played his 100th and final game for the Blues in last Thursday night's win over Essendon and appeared emotional in the rooms after the match as he spoke to his teammates.

"Thanks for all the good times over the past eight years," De Koning said in his speech.

"Obviously a disappointing year but yeah, keep going and doing good things. All the best."

On Wednesday, five days after Carlton's season ended, De Koning informed the club in his exit meeting that he is leaving.

"To be really honest, this has been the toughest decision I have ever had to make, leaving a club I've loved being part of over the last eight years, with friendships I will take with me for the rest of my life," De Koning said in a statement.  

"In the end I have made a decision that is best for me, but I just really want to take this opportunity to thank the entire Carlton community who has embraced me since I was drafted."

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St Kilda's bold plan to secure players with big money appears to be paying off after recently retaining star Nasiah Wanganeen-Milera for a further two years.

Wanganeen-Milera was heavily pursued by Adelaide and Port Adelaide, but the 22-year-old decided against moving back to South Australia.

St Kilda is also favourite to win the services of West Coast premiership forward Liam Ryan, who on Tuesday told the Eagles he wanted to leave the club despite having a year to go on his contract.

"We're very pleased that Tom has nominated St Kilda as the club where he wishes to continue his career," Saints footy boss Dave Misson said.

"As Tom is a restricted free agent, Carlton will have the opportunity to match our offer once formally submitted. That is part of the process and something we are fully respectful of.

"With the official player movement period still several weeks away, it would be inappropriate to comment further at this time."

De Koning's decision follows that of father-son Jack Silvagni, who told the Blues on Tuesday he would be seeking a fresh start under free agency.

Silvagni is the third generation of his family to play VFL/AFL football for Carlton, following in the footsteps of his grandfather Sergio, and father Stephen. -with AAP