ST KILDA defender Sam Fisher will undergo a test to prove his fitness later this week after sustaining a back injury on the weekend.

Fisher was bending over for a contest in the first half of Sunday’s VFL game between Sandringham and Williamstown when he suffered a disc injury to his lower back.

He underwent scans on Monday where it was found he had suffered no serious damage.

[ RELATED: Full injury list ]

The injury was not related to the hamstring troubles he has had for much of 2014.

After the inflammation around Fisher’s back subsides, he will be tested later in the week.

"Obviously, Sam has experienced a somewhat frustrating season with injury so far, but we are confident that this will only be a temporary setback in his return to AFL football," St Kilda Head of Football Chris Pelchen said.

Young Saint Daniel Markworth is also set to be sidelined for a significant period of time after he was also injured while playing for the Zebras.

Markworth suffered a severe hamstring injury that will rule him out for 9-10 weeks. The injury was to his right leg – the same leg on which he injured his knee in late 2012.

The two injuries are not related as Markworth had a patella graft, as opposed to a hamstring graft when he had the ACL surgery in December, 2012.

"Daniel has already confronted some challenges in his relatively short career so we expect that he will overcome this injury with the same level of commitment and professionalism as he has previously displayed," Pelchen said.

Tom Simpkin has been cleared of any shoulder damage after coming off early in last week’s loss to West Coast. Simpkin was subbed off during the Sunday’s clash, mainly due to a shoulder problem but will be fit to take on Richmond this week.

First-year player Luke Dunstan will also be available for selection after missing last week’s game against the Eagles.