SCANS have confirmed St Kilda ruckman Tom Hickey is likely to miss the rest of the season with a left hamstring tendon injury.

Hickey, 27, was hurt in the second quarter of last Saturday night's loss to the Western Bulldogs while diving to tackle Lachie Hunter.

He returned to the field to help with rotations, as young forward Josh Battle was ruled out early after being concussed in a clash with Dale Morris.

Hickey played 13 games this season and is contracted for next year.

With Billy Longer sidelined for 2018 after ankle surgery, a spot has opened up for rookie big men Rowan Marshall and Lewis Pierce.

Marshall has lined up in nine matches this season, largely up forward but also in the ruck and down back.

Meanwhile, Pierce has spent the year at Frankston, rather than the Saints' VFL affiliate of Sandringham.

The move was decided upon to allow Pierce to play in his preferred position in the ruck, with others ahead of him in that spot at the Zebras last year.