ST KILDA veteran Sam Fisher has undergone scans on Monday after his return from injury in the VFL was cut short by back spasms.

The 31-year-old, who has not played at AFL level since round 10 last season, made a bright start in Sandringham's loss to Williamstown on Sunday but did not return after half-time.

The defender suffered a repeat hamstring injury in the opening minutes of his previous comeback game in the VFL six weeks ago.

St Kilda is yet to release the details of his latest scans, but another potential stint on the sidelines places his playing future in doubt as the Saints settle their back six with recruits Luke Delaney and Josh Bruce.

The two-time club champion missed 14 games last season with a foot injury and back and hamstring injuries restricted his pre-season and have dogged him since.