CARLTON has moved to lock in gun defender Jacob Weitering for the long term, with the No.1 pick signing a mega-contract extension.

The important Blues backman has enjoyed a stellar 2020 season, putting him in Virgin Australia AFL All Australian contention for the first time.

His four-year contract is due to expire at the end of next year but, as revealed first by AFL.com.au, he has agreed to an extra four years with the Blues.

The extension will make him a Blue until the end of 2025 and lock him in well past 2023, when Weitering would have reached free agency for the first time.

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Signing Weitering is one of new Blues list boss Nick Austin's first major moves since he joined the club earlier this season as the club prioritises the 22-year-old.

Austin is spearheading the Blues' list management team alongside Michael Agresta as Carlton's national recruiting manager.

Weitering's deal is a fillip for the club, with a number of key Blues set to fall out of contract at the end of next year, including co-captains Patrick Cripps and Sam Docherty, top-10 pick Sam Petrevski-Seton and skilful forward Zac Fisher.

Weitering has been among Carlton's best performed players this season, emerging as a star of the competition in defence and limiting some of the best forwards in the AFL.

He was the first choice in the 2015 NAB AFL Draft after being a standout player for the Dandenong Stingrays and this year joined the Blues' leadership group.

Carlton has a number of senior regulars who remain out of contract beyond this season.

As revealed by AFL.com.au last month, veterans Marc Murphy and Levi Casboult will sign new one-year deals with the Blues while Lachie Plowman is also due to for an extension.

Matthew Kreuzer, Eddie Betts and Kade Simpson are unrestricted free agents at the end of this season, while Matt Kennedy, who has enjoyed solid form in recent weeks, is also unsigned beyond 2020.