Collingwood and Melbourne have been hit with a bout of illness just days out from their Round 6 matches, with a Demons superstar and two key Magpies missing training on Friday.

Collingwood captain Dary Moore and fringe tall Nathan Kreuger have both been battling illness, with Moore having to leave training early due to the issue, according to 9 News' Josh Dawe.

The worry comes a week after midfielder Jordan De Goey was forced to miss his side's Gather Round clash with St Kilda due to gastro, while first-year player Ed Allan didn't play at VFL level last week due to COVID.

Four days out from their blockbuster Anzac Day clash with Essendon, both Moore and Kreuger will be in a race against the clock to be fit and healthy in time for Tuesday's clash.

Moore's significance to Craig McRae's side is paramount, while Kreuger was seen as a potential inclusion to fix the Magpies' current ruck woes, with Darcy Cameron, Mason Cox and Aiden Begg all unable to play.

Kreuger made his return to the field from pre-season shoulder surgery last week in the VFL to place himself in the mix for a comeback at AFL level.

Collingwood isn't the only side to be battling with illness as Melbourne ball magnet Clayton Oliver trains away from teammates over the weekend due to an ailment of his own.

While expected to line up for the Demons in Monday night's Anzac Day eve encounter with Richmond, the club will be needing to monitor the four-time best and fairest winner's fitness over the coming days.

Melbourne have managed to welcome the returns of Max Gawn (knee), Jake Lever (ankle) and Michael Hibberd (Achilles) for their Round 6 clash, with their final 22-man side to be confirmed on Saturday evening.