CARLTON fullback Bret Thornton has been a part of Blues backlines destroyed by St Kilda far too often for his liking in the past five years.

Thornton acknowledges he could be in for another tough game on Friday night at Telstra Dome, when he stands alongside one of Fraser Gehrig, Nick Riewoldt or Justin Koschitzke.

But he hopes the Blues' saviour will be the man he rates the best key forward in the league, his team-mate Brendan Fevola.

"His greatest asset is his pace off the mark, he's probably one of our quickest players over 15 metres," said Thornton, who goes head to head with Fevola at Carlton training.

"The strength of his marking, if you're caught behind, then he very rarely drops them. He's got a great pair of hands

"Hopefully he can kick a bag for us tomorrow.

"I reckon he's one of, if not the best, full-forwards in the comp at the moment.

"Another good asset of his is his kicking. He can mark it anywhere around 60 metres and be a chance to kick it, so that makes him even more dangerous than a lot of the other players."

Carlton's best chance of levelling the ledger against the Saints' big forwards comes through injuries as St Kilda lacks an obvious match-up for Fevola with Matt Maguire, Max Hudghton and Sam Fisher all sidelined due to injury.

However the Saints will draw confidence from their utter dominance over the Blues the past five seasons.

St Kilda has beaten Carlton by an average of more 10 goals in seven games since 2002, and last season whipped the wooden spooners by 82 points.

Riewoldt and Gehrig have both bagged hauls of nine against Carlton in recent seasons, and Thornton conceded St Kilda's stranglehold was "certainly not flattering at all for us".

"We've been a bit thin down back over the last few years with Riewoldt and Gehrig in their side and then being able to win the ball in the middle, that's been a big factor," he said.

"But our side has changed a lot, so hopefully that should hold us in better stead."

One of the additions to the Carlton side is key defender Setanta O'hAilpin, whose build, speed and athleticism make him an option for Riewoldt after opposing Brisbane Lions star Jonathan Brown in round five.

"That's one of his biggest pluses, Setanta, his natural athleticism," Thornton said.

"That's why Riewoldt is such a good player, because he's able to cover the ground and his fitness as well, so that could be a good match-up."

Thornton said the game was a must-win for the Blues if they wanted to keep alive their chances of reaching the finals.

"If we can be 3-3 (wins-losses) after six, at the start of the year we definitely would have taken that," he said.

"On the other hand if we lose and go 2-4, then we're really staring down the barrel a bit, so tomorrow night is really a massive game."

Carlton will wear predominantly white tomorrow night to avoid a jumper clash.

It will be just the second time Carlton have not worn navy blue - the first came a decade ago, when they wore sky blue for a chocolate promotion.