THERE are no guarantees that both Ben Reid and Mason Cox will return for Friday night's clash against Carlton, according to Collingwood coach Nathan Buckley.

However, the Magpies believe the pairing of Reid and Cox up forward – with big man Brodie Grundy playing largely in the ruck – is a sustainable one in the long-term. 

Reid was a late withdrawal ahead of last week's 16-point loss to Greater Western Sydney after he copped a knee from Cox in his hip at training.

Cox was ineligible to play against GWS after being suspended for a high hit on Hawthorn's Daniel Howe in round one – a game in which the tall Magpie struggled to have an impact. 

"Whether it's a six-foot-two player or a six-foot-six player, it's about your ability and capacity to bring the ball to ground," Buckley said. 

"We know both Mason and Ben are aerially our best forwards, the guys that are going to do the most damage in the air. 

"Whether we go with one or both is going to be horses for courses but it's a structure we believe works for us, so we'll find out."

The Magpies will be forced to make at least two changes to the side, with Darcy Moore (hamstring) and Tim Broomhead (broken leg) certain omissions after last week's loss to the Giants.

Collingwood has been decimated by injury to open the season but, as Buckley put it, there are "blue skies on the horizon".

Jordan De Goey and Jamie Elliott will play 75 per cent of game time in their first hit-out in the VFL for the season against the Northern Blues on Saturday. 

Chris Mayne will also be available at senior level or in the VFL after succumbing to a quad injury late last week, while Alex Fasolo is in the mix to play his first game of the season. 

However, veteran midfielder Daniel Wells is still one-to-two weeks away as he looks to build his conditioning after Achilles/calf problems affected his preparation. 

In good news for the Magpies, Kayle Kirby was back at the Holden Centre on Wednesday following a significant health scare when he collapsed behind play in a VFL practice match on Saturday. 

Kirby was rushed to hospital after suffering an irregular heart rhythm in the Magpies' VFL clash against North Melbourne. 

Buckley said it was too early to forecast Kirby's return to the field and added he would undergo a few more tests to determine the cause of the collapse. 

"His heart-rate rhythm has stablised. That was clearly a shock for him and some of his teammates," Buckley said. 

"Credit to our docs and paramedics who came along and our support staff, who were contacting his family and his mates to set everyone's mind at ease. 

"He was back at the club today and looking well and getting back into the swing it.

"Clearly it's a bit of a shock for him and clearly there's a few investigations to find out what caused it, to make sure we can adequately prepare him and us for any further eventualities, which we're not expecting."