ST KILDA must start bridging the "massive" gap between its best and worst performances, coach Alan Richardson says.

Ahead of Monday night's clash against Carlton at Etihad Stadium, Richardson has put the heat on his players to atone for their terrible effort against Hawthorn last weekend.

The Saints suffered a 145-point mauling at the hands of the Hawks and have endured a tough week on the training track as a result.

"We didn't want to lose any more (players to injuries) on the training track but when you have a performance like that, you've got to take the risk and we needed to crack in," Richardson said on Sunday.

"It was really disappointing last weekend and it's one of those weeks where there's a bit of soul-searching.

"We've reviewed the performance really strongly. It's a very young group.

"We've got some experience at the top that drives that look for improvement and look for growth but underneath we've got some really young players.

"At times we're going to be inconsistent but we're not going to be, or don’t want to ever be, inconsistent with our effort, and that was the part that disappointed us.

"So it's an opportunity to atone.

"The gap between our good and bad at the moment is massive, so that will be a real focus for us."

The Saints have made four changes for the clash with the Blues, with Luke Dunstan, Arryn Siposs, Josh Bruce and Cameron Shenton replacing Jarryn Geary, who has an elbow injury, and Shane Savage, Tom Simpkin and Josh Saunders, who were all omitted.

St Kilda has won 16 of its past 19 games against Carlton, which Richardson said could help his team.

"I think in the back of the players' minds, maybe it counts for a little bit," Richardson said. "But we've gone through and looked at the opposition like we always do.

"You can imagine, given the week we’ve just had, that it's much more about us than it is about them and that's where we're at."

A shining light in recent weeks has been youngster Tom Curren and he is likely to get the big tagging job on Carlton skipper Marc Murphy.

"He's only a young man but his concentration and discipline and commitment to his teammates has been outstanding, and there's a fair chance that he'll go to 'Murph'," Richardson said.

Richardson said he believed playing in a stand-alone Monday night fixture "probably excites the players. We haven't had too many of those opportunities.

"But the reality is that when you have a performance like we did last week, everything is about addressing that, and rebounding and responding to that performance.

"Our physicality was off, our defence was really poor, so it's not so much about the venue, the opposition or the opportunity we have one-out on Monday night.

"It's about responding to last week."

Defender Sam Fisher will be sidelined for at least another month after his hamstring injury flared again during his comeback match in the VFL last weekend.

"When he gets to that next stage of intensity or load, he just keeps failing," Richardson said.

"It's a really conservative approach now with Fish."