CARLTON will have to beat St Kilda without Charlie Curnow in order to seal a finals spot after the gun forward failed to overcome an ankle injury.

Curnow had been named on Thursday to return for Sunday's game at Marvel Stadium, but was officially ruled out on Friday.

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It's a hammer blow to Carlton's hopes of locking in a top-eight berth, while Mitch McGovern (hamstring) also appears unlikely to get up.

The Blues can seal finals with a win, but a loss to the in-form Saints will give Fremantle a chance to leapfrog them.

"I'll start with the bad news, Charlie's not playing. So that's the not-so-great news," coach Michael Voss said.

"We sort of thought that he might be able to pull up pretty well from some of the things that he did the other day, but hasn't pulled up as well as what we expected.

So we'll just make that call now and obviously it gives us an opportunity to be able to lock in on what our forward mix is going to be. So obviously banking in that we can get the job done a couple of times in a row."

Harry McKay (quad), Jack Martin (hamstring), Lachie Fogarty (collarbone), Jordan Boyd (adductor), Tom De Koning (foot/lung), Adam Cerra (hamstring) and Matt Cottrell (shoulder) are also sidelined.

Voss wouldn't rule Sam Docherty, who suffered a third ACL tear in March, out of making a comeback in finals if the Blues make it.

Brodie Kemp, who kicked four against the Eagles, will stay in attack but the Blues believe Curnow will be fine to play in the first week of finals if Carlton qualifies.

"It's something that he's obviously had to manage for a little while, but just feel like we just need to give it that little extra (time to) settle so it can settle down a little bit more," he said.

"But that'll be three, four weeks, after his last incident. So feel pretty confident that obviously the best-case scenario getting through and playing, that he'll be fit and available."

McGovern (hamstring) didn't train with the main group and clearly appears in some doubt to play.

"We'll give him every opportunity to be able to get up," Voss said.

Corey Durdin dislocated his shoulder against West Coast and is also touch-and-go.

Adam Saad is expected to return after a week out with a "very low-grade" hamstring injury with Voss saying Carlton had opted not to risk him on a flight to Perth.

"He'll play," Voss said.