FOR a player who had only kicked eight goals from 161 games before this season, Bret Thornton has undergone a remarkable transformation to become Carlton's swingman.

The long-term defender has been used at both ends of the ground this season, kicking 12 goals, two of which came in last week's elimination final win over Essendon.

But with West Coast's top-heavy forward line to contend with this week, he knows he is just as likely to find himself down back again.

"They're probably the tallest forward line in the League. They have got four or five blokes who can really mark the ball so there might be a few changes with us," Thornton said at Tullamarine Airport before boarding a flight to Perth.

"I think our defence has been really good lately. We've been good at getting the ball to ground … and I think that's going to hold us in good stead."

And if coach Brett Ratten already has a firm idea where he plans to use Thornton on Saturday night, it's a secret that even the 27-year-old doesn't know.

"I'm not sure. I never know. Ratts tells me before the game and says be ready for both ends," he said.

The Blues were convincing winners over Essendon last week after much speculation centred around Ratten's coaching future if the Bombers managed a surprise win.

Despite that conjecture now being out of the way, Thornton said the lead-up to this week's game had been no different.

"We want to go as far as we can in this finals series. Last week is just a memory now. We're fully focused on West Coast," he said.

"If we don't play like we did last week we're not going to get anywhere near them. We've got to start well and silence the crowd. That will help us."

Injured Blues Bryce Gibbs and Matthew Kreuzer will miss the game after they weren't sighted at the airport with their teammates but Thornton said Carlton would not be in the position it was in if it didn't have depth.

"Those two are going to be big losses. Gibbsy kicked three goals last week and he's been great for us," he said.

"But that's the sign of a good team so whoever gets their chance, we are confident they can play just as well."

The views in this article are those of the author and not necessarily those of the AFL or its clubs