CARLTON is poised to emerge from the injury crisis that threatened to derail its season with up to four key players in the frame to return for Sunday's encounter with the ladder-leading Sydney Swans.

Jarrad Waite (back), Andrew Walker (calf), Kade Simpson (jaw) and Mitch Robinson (calf) are all in the selection mix for the important clash, which is music to the ears of coach Brett Ratten. 

"The tide might be turning a little bit and now players are starting to come back, which is great," Ratten said from Visy Park on Wednesday.

"[Marc] Murphy's had three weeks back … [Chris] Judd's not far away to come back, Waite's close - it's starting to turn a little bit for us.

"Our major session is on Thursday so those blokes that are very close in Waite, Walker and Robinson will be tested and Simpson has got the all clear, which is great.

"We've just got to get him through that final session to see if he's up and ready to go."

Walker and Simpson, if selected, will make their returns earlier than had been expected in a major boost to the Blues' chances of mounting a successful late surge back into the top eight.

Waite had not played since played since injuring his back during the Blues' game against St Kilda in round seven.

He had 13 disposals and six marks and kicked two goals during the Northern Blues' 99-point victory over VFL rival Coburg Tigers last weekend.

Waite joined teammates at Visy Park on Tuesday for light skill work. If selected, he'll play his 150th game.

"Even just watching the Northern Blues last weekend - to see him patrolling that forward line with the way he moves - it just gives you a lot of hope," Ratten said of Waite.

"He's such an influential player on the team and the way they go about it. [He] just helps us become more potent up forward. He's a terrific player and we've got to get him out there."

Northern Blues coach Darren Harris told carltonfc.com.au: "He got through a full week of training week before the VFL game and has pulled up well today, which is a very encouraging sign.
 
"His performance on the weekend was solid across all four quarters.
 
"I think the real positive was late in the game, when he was putting a lot of pressure on it and was still able to run and play good football."

Carlton's season was on the brink after a disappointing loss to North Melbourne in round 16 that also saw Judd suspended for four weeks for his chicken wing tackle on Leigh Adams.

An undermanned Blues' side has defied the odds to breathe new life into its season with wins over the Western Bulldogs and Richmond, but it faces a rise in class against the Swans.

"Every time you play Sydney, every year they're in the finals, so their record and what they've done as a football club has just been outstanding," Ratten said.

"Their form this year … somehow they just seem to find a way [to win]. Their form has been outstanding.

"I think it's a great challenge for us because of the way they play and how competitive and how combative they will be.

"It will be a great challenge for our group."

Ruckman Rob Warnock missed last week's VFL game with a sore shoulder, but is fit for selection this week.