CONTINUING groin soreness for St Kilda midfielder Blake Acres will force him to miss the next month, while defenders Jake Carlisle and Sam Gilbert have also been ruled out of facing Collingwood on Saturday night. 

Carlisle, 26, was concussed in the round eight loss to Fremantle after copping an errant Nat Fyfe knee and was ruled out for the rest of that game.

Meanwhile, Gilbert has had surgery on his right thumb for ligament damage and will miss six weeks.

MATCH PREVIEW: Are the Saints a chance to find form this week?

Acres missed the round seven loss to Melbourne with groin soreness but trained in the lead-up to last week's match in his home state of Western Australia and collected 23 disposals while spending time opposed to Fyfe.

"Blake was rested for the round seven clash with Melbourne, which the club hoped would resolve the issue," St Kilda football manager Simon Lethlean told saints.com.au.

"But after reporting soreness following the match against Fremantle on Saturday night, the club has opted to give him an extended break to rehab the injury.

"Blake has shown some promising signs this year and we hope with a period of rest, he can recapture that form on his return."

Carlisle trained away from the main group on Thursday and couldn't convince St Kilda he was fit enough to play.

The backman is ranked ninth in the competition for intercepts per game and has been one of the few at the club to perform well this year.

His ability to swing forward when needed will also be missed.

Carlisle is not the only Saint to be dealing with concussion, with key forward Paddy McCartin at least a week away, while midfielder Koby Stevens is out indefinitely.

Gilbert, 31, faces an extended stint on the sidelines.

"After consultation with a surgeon, we felt the best course of action for Sam was to have it repaired surgically," Lethlean said.

"We've lost a little bit of experience with Dylan Roberton also out of the team, but pleasingly we have a number of defenders performing well at VFL level."

Bailey Rice, the son of former Saint and Blue Dean, will debut against the Magpies.

St Kilda is languishing in third-last with just one win and a draw on the board.

Hard nut Nathan Wright will return to VFL action after being managed last week.