Collingwood concede there is significant doubt over star midfielder Jordan De Goey featuring in their late AFL finals bid because of an ongoing groin complaint.
De Goey was named to play against Richmond on Sunday but failed a fitness test 24 hours before the match and was withdrawn from the side.
His replacement, first-year forward Joe Richards, then withdrew through illness in a situation Magpies coach Craig McRae said was "not ideal".
Collingwood went on to post a comfortable 14.9 (93) to 9.13 (67) win over the last-placed Tigers at the MCG, keeping their troubled premiership defence alive.
But flag hero De Goey is no certainty to return for the Magpies' high-stakes clash with Carlton on Saturday night.
The 28-year-old has been limited to 12 appearances this season and has struggled to have his usual explosive impact when available.
McRae admitted there were question marks over De Goey when quizzed on the star after the win over Richmond.
"It's difficult to know what's going on there for me ... other than he looked really sore this week," McRae said.
"He's been looking really sore early in the week and we're de-loading him and running straight lines and getting him to the line.
"But this week he looked really sore, so we'll work through that."
McRae was hopeful a week off would help De Goey reset.
He said Magpies strength and conditioning boss Jarrod Wade would likely provide a more detailed assessment of his fitness battle in the coming days.
"Each week seems to start in the same place and maybe not playing this week might help us start in a different place," McRae said.
"But again, we'll wait and see on that."
Collingwood are bracing for a momentous week, with club great Scott Pendlebury set to reach the 400-game milestone when the Magpies play old rivals Carlton.
Pendlebury had been set to start as the substitute against Richmond, but was called into the starting side when De Goey was ruled out.
The 36-year-old was eventually tapped out at three-quarter time and will back up against the Blues in front of an expected crowd of about 90,000.
"I'm keen to stay here for the moment but I'm well aware that this is a big game for our footy club," McRae said.
"We'll celebrate the individuals that we need to and pay respect to the game."
Collingwood's win over Richmond snapped a four-match losing streak and improved their record to 9-8-2, keeping them within reach of the top-eight.
But they face a tough run home, with games against Carlton, Sydney, Brisbane and Melbourne to come.
"We've taken a step forward but there's more steps to be taken," McRae said.
"We got stuck for a few weeks. We got stuck in ourselves and it was nice to step forward."
