JUST a week after St Kilda struck out in its pursuit of North Melbourne ruckman Tristan Xerri, the club has turned its attentions towards his former Kangaroos teammate Tom Campbell.

AFL.com.au understands the Saints have remained determined to bolster their ruck stocks after the Trade Period and have homed in on Campbell, who was discarded by the Kangaroos earlier this week, as a delisted free agent.

WHO'S CALLED IT QUITS 2021's retirements and delistings

It comes after St Kilda targeted a move for Xerri throughout the two-week exchange window, only to be turned off by North Melbourne's asking price of a future second-round pick for the contracted youngster.

Xerri had formally asked the Kangaroos for a trade and had agreed to a two-year deal with the Saints, only to be told he was a required player at Arden Street to provide ruck depth behind Todd Goldstein and the recently acquired Callum Coleman-Jones.

The retention of Xerri meant that Campbell was released at the end of his contract by North Melbourne, with the 29-year-old then identified by St Kilda as an option to provide support for veteran Paddy Ryder and young star Rowan Marshall.

Campbell had previously been recruited as a Pre-Season Supplemental Selection Period signing by North Melbourne on the eve of its 2019 campaign, playing 12 games across three years for the club.

KEY DATES When does the delisted free agency period start?

Prior to that, the 201cm ruckman had played 42 games throughout a seven-year stint with the Western Bulldogs including nine senior appearances in the club's successful 2016 premiership season.

St Kilda has been focused on improving its ruck stocks this off-season, with Ryder – who turns 34 next year – the only senior support for Marshall aside from rookie duo Paul Hunter and Max Heath.

Veteran ruck option Shaun McKernan retired in August, rookie Sam Alabakis was delisted in September, while Hunter remains uncontracted heading into next year.