Port Adelaide are understood to be showing interest in St Kilda free agent Jack Billings.

It is understood that the Power have "preliminary interest" in the Saints midfielder's services, according to Fox Sports' Tom Morris.

The 25-year-old remains unsigned at Moorabbin past this season despite St Kilda having reportedly placed an extension to him.

Billings is reported to be keen to remain in the red, white and black, but the former Oakleigh Charger and St Kilda are yet to reach an agreement.

PLAYER MOVEMENT: Crows veteran to assess options for future

According to Morris' report however, multiple list managers within the AFL are of the belief that the Saints are trying to part ways with Billings in initial offering a deal that is south of what he is worth.

Currently sidelined due to a hamstring strain, Billings could have already played his last game for St Kilda, with a return this season seen as an uphill battle.

Should Billings opt to take up his free agency rights and depart St Kilda this off-season, the Saints would be handed draft compensation by the AFL.

MELBOURNE, AUSTRALIA - JULY 13: Jack Billings of the Saints runs out onto the field during the round 17 AFL match between the St Kilda Saints and the Carlton Blues at Etihad Stadium on July 13, 2018 in Melbourne, Australia. (Photo by Quinn Rooney/Getty Images)

Billings joins the likes of Seb Ross, Luke DunstanJake CarlisleJarryn Geary and Darragh Joyce in being out-of-contract at St Kilda this season.

The Saints onballer is one of only four restricted free agents remaining this year, with Giants superstar Josh Kelly, Crows midfielder Matt Crouch and Swans utility George Hewett also falling into the category.