CARLTON coach Brett Ratten says captain Chris Judd will "play for sure" this Friday night against St Kilda, while midfielder Andrew Walker is in the mix for a return to the seniors.

Ratten said Judd was a certain starter after overcoming concussion received in round 13, while Walker was in line for a recall after playing two games in the VFL following a shoulder injury sustained in the pre-season.

"Chris has come back in fantastic order," Ratten said on Tuesday.

"He's fresh; he's probably trained the best he's trained this week at the club.

"The break has done him the world of good, mentally and physically. Now his brain is all back in order and he looks vibrant and enthusiastic again.

"[Walker] will be right in the mix. It's one of those ones whether we bring him in this week or leave it for one more week, so it will either be this week or next week. We need to determine that later today."

Ratten said there were two challenges for Blues this weekend – they haven't beaten the Saints since round 20, 2001, and they struggled at the start of their first match after the Hall of Fame break in May.

"The challenge for us is the last break we had, we came back and played Brisbane on the rebound and we got smashed by 37 points in the first quarter. We had to work our way back in the game and we couldn't do it," he said.

"Regardless of who we're playing, I think the break for us last time wasn't great, and we'll see what happens this time."

The Blues' coach said he thought his players had trained well since returning from their mid-season hiatus, but emphasised good form on the track was often not a direct indication of how game day form would transpire.

He said the coaching staff had made a few alterations to the training schedule the club had adopted during the first break this year.

"We changed it a little bit. Saturday's training, we did a few different things and probably went a little bit lighter," he said.

"We have changed it marginally."

Ratten said the Blues would benefit from the fact Friday night's match would be played at the MCG, rather than St Kilda's favoured ground at Docklands.

He also said his side was "fitter across the board" than it was when it suffered a 40-point loss at the hands of the Saints in round two.

"We've played them a lot at Telstra Dome too, and the history says they play very well there," Rattern said.

"In the last five or six seasons they've had a very good record there, so it's a good one for us to get them at the MCG, different venue, and I think we're in a different state as well to the way we play.

"They've had a great record against us and that's the challenge for our players, if we can swing that around."

Ratten also said he wouldn't hesitate to note to the players that the Blues had a chance to end a lengthy hoodoo this week, as they had already wiped out a handful of negative records this season.

"I think sometimes in football, we shy away from it with, 'Don't say it, don't say it, everyone will think this'.

"But at the end of the day, you've got to do something about it or you'll keep copping it.

"We speak about it, and that's the challenge to the group, if they can rectify it and change it."