COLLINGWOOD will be without Steele Sidebottom and Jamie Elliott for this weekend's trip to Perth, but key defender Billy Frampton is expected to be available for the clash against West Coast at Optus Stadium.
Sidebottom was subbed out of the Magpies' 35-point win over North Melbourne at Marvel Stadium before quarter-time after injuring his knee in a tackle.
The 32-year-old underwent scans on Tuesday that have confirmed a medial collateral ligament sprain that will sideline him for at least six weeks.
Collingwood will have a clearer timeline around the veteran's return date once the swelling in his knee settles down next week.
Magpies senior assistant coach Justin Leppitsch, who stood in for ill senior coach Craig McRae at Wednesday morning's scheduled media conference, said the club was more likely to be cautious with the veteran.
"The positive is he's back at the right time of the season for us to be fresh and get the body ready," Leppitsch said of Sidebottom.
Sidebottom became just the fourth player in the history of the Collingwood Football Club to reach 300 games – after Scott Pendlebury, Tony Shaw and Gordon Coventry – but his milestone didn't go to plan and he won't return before the round 17 clash against the Western Bulldogs at the earliest.
Sidebottom had been firmly in the All-Australian conversation – if the selectors went with a pure wingman – heading into round 11, along with teammate Josh Daicos, St Kilda's Mason Wood and Essendon's Nic Martin, but will now miss too much football to be considered for a second blazer after earning his first in 2018.
Elliott injured his shoulder against the Kangaroos and won't head west this weekend to face the Eagles, who have won only one of their first 11 games.
"It's not too bad at all (Elliott's shoulder), he's been managing it for about a month, but given the six-day break and the travel and hadn't pulled up as well as it previously had, we decided that this is the week probably best not to play," Leppitsch said.
Off-season signing Frampton has missed the past three games with a groin injury but is on track to be available for Saturday's game against West Coast if he completes training this week.
The former Adelaide and Port Adelaide utility has been a revelation at the AIA Centre since move to the club in October, proving himself as a key defender as well as helping solve the ruck crisis at the club in the early months of the season.
Craig McRae's side cruised to a seventh consecutive victory on Sunday to exit round 11 three games inside the top four after Brisbane and Melbourne stumbled.
Collingwood will be forced to make some difficult selection decisions either side of the bye with a handful of players returning from injury.
Patrick Lipinski is set to resume full training this week and could be ready for some game time as soon as King's Birthday after missing the first half of the season due to a shoulder reconstruction, following an injury against Hawthorn in a practice match.
After a positive recent review with a finger specialist, Dan McStay is on track to return for the blockbuster against the Demons.
Jeremy Howe hasn't played since being carried off the MCG with a horrifically broken arm in round three but the veteran defender is building towards being available after the bye after increasing his time on track at the AIA Centre in the past fortnight.
Ash Johnson, Jack Ginnivan and Oleg Markov weren't in Collingwood's best 22 early in the season when everyone was available, but have produced strong games since then, highlighting the impending selection conundrum at the Magpies.
Leppitsch said McRae was in no danger of missing the trip west to face the Eagles with the illness that kept him from the club on Wednesday.
"He's just a little unwell," Leppitsch said of McRae.
"It's not bad. You just figure stay away, obviously things can get contagious, potentially, so nothing that's going to stop him from being there this weekend.
"He'll be fine by the time we get on the plane."