The Magpies are already forced into making at least one change for this weekend's clash against the reigning premiers, with star midfielder Nick Daicos set to miss up to six weeks with a hairline fracture in his knee.
Defender Nathan Murphy was also placed in doubt to face Geelong due to an ankle injury that was also sustained in last Saturday's loss to Hawthorn, however the Magpies backman remains in the mix for selection for Round 22.
On Wednesday McRae confirmed Sidebottom won't be named, doubling the Magpies' midfield concerns following Diacos' setback.
"Steele won't play," the Magpies coach said.
"He's got a sore foot. If we had an extra couple of days (of recovery) he'd be available.
"He's been carrying it for a couple of years. Every now and then it gets a bit grumbly, and right now it's a bit grumbly.
"He just needs a bit of extra time to recover. Hopefully he's right next week."
Daicos' older brother Josh looms as the best-suited teammate to take on the young star's role under McRae for the coming rounds, however Sidebottom's absence only raises the reliance on Josh Daicos' role as the opposing wingman in McRae's system.
Siblings, shadows and stepping out.
— Ed Carmine (@ed_carmine) August 8, 2023
Collingwood's selection committee is likely to look toward fringe midfielders Trent Bianco, Josh Carmichael or Finlay Macrae, with the latter two needing to prove their fitness this week after battling hip and thumb injuries respectively.
McRae labelled Murphy's potential availability as "remarkable" after his home and away campaign intially looked over due to a low-grade syndesmosis diagnosis.
The Magpies rested fringe defender Billy Frampton from last Sunday's VFL hitout due to Murphy's injury, with both backmen now in the mix to face the Cats.
"The doctors said 2-3 weeks, it ended up being 2-3 days. It's quite remarkable," McRae said.
"He got through training, it'll be whether he pulls up well. We'll see how that goes, it'll be hard not to pick him if he pulls up well.
"There might be room for both (Murphy and Frampton), we'll just have to see what team they pick and we'll work through that this afternoon.
The Magpies will announce their squad on Thursday evening, while the club is yet to confirm the extent of Sidebottom's setback.