St Kilda are set to offer young forward Paddy McCartin a two-year contract extension that will see him remain at the club until the end of the 2020 season.

The 21-year-old is already contracted for next season, with the extension set to show McCartin the club are committed to him for the foreseeable future.

Fox Footy's chief AFL journalist Jake Niall reported the news on Thursday night, and said club sources revealed that while the two-year deal wasn't confirmed, it appears the most likely length of his new extension.

Niall reported St Kilda are very keen to lock away McCartin, and are hopeful talks can progress soon.

McCartin has only played five games for the Saints so far in 2017, with concussion problems and team balance the two main factors for his lean run in the seniors.

The club are unsure whether the key forward will return to an AFL field this season, with his return to football likely coming through the VFL - he hasn't played a game since June 24.

Since being selected by the Saints with the first pick in the 2014 national draft, McCartin has played just 22 AFL games, with 11 of those coming last year.

The key forward's career has been hampered with concussions so far having suffered six head knocks since 2014, with his last concussion coming six weeks ago in the VFL.

With Nick Riewoldt retiring at the end of the season, the Saints will look to McCartin to fill the void of the outgoing champion, alongside Josh Bruce and Tim Membrey.