Watch Mick Malthouse speak to the press on Friday

VETERAN Anthony Rocca is in doubt for Collingwood's ANZAC Day clash with Essendon at the MCG, however, supporters might see the debut of 2008 first-round draft pick Steele Sidebottom.

Coach Mick Malthouse confirmed on Thursday that Sidebottom was a chance to line up against the Bombers as question marks remained over the fitness of some of his squad ahead of round five.

Malthouse said that Rocca, who played his first game since round 13, 2008 in the Pies'  win over the Brisbane Lions, had pulled up sore from a bump he received in that game.

“He was injured last week ... so we've got to take that into consideration,” he said.

“We knew that by playing him last week he may not be able to come up this week.”

Rocca is just one Magpie whose fitness will be closely monitored in the next 48 hours.

Heath Shaw (hamstring) is already certain to miss, Paul Medhurst is trying to shake off the effects of concussion while Alan Didak, who sat out a large part of last week’s final quarter against the Brisbane Lions, also trained away from the main group on Wednesday.

Collingwood will name its team on Thursday night but a training session on Friday will determine the side’s final make-up.

“I don’t think anyone's a definite until they train tomorrow,” Malthouse said.

“I don't want to go into an area where I'm declaring 100 per cent that's the 22 because too many things happen.”

When asked if he would consider playing a debutant – such as Sidebottom – in a big occasion such as the ANZAC Day fixture, Malthouse replied: “I've done it before”.

Malthouse said several of Collingwood’s players in action in the VFL competition had shown form in recent weeks.

“We will pick the fittest side we can on match day,” he said.

The Collingwood coach noted that previous ANZAC Day battles – irrespective of the two teams’ ladder positions – had always been close.

This year both teams entered the clash in a similar position and Malthouse said the occasion was likely to lift players of both sides.

“It seems to bring out the best in people and we’ve seen some sporting heroic acts which have sometimes determined the state of the games,” he said.

“It’s very difficult to explain but, believe me, when The Last Post is played the hair on the back of your neck stands up and you are very much fully aware of the occasion.”