The Bulldogs confirmed on Tuesday afternoon that Macrae would be unable to suit up for the Round 24 encounter after suffering a head knock in last week's shock loss to West Coast.
The club revealed Macrae has been battling with concussion symptoms since the defeat, with the midfielder having been subbed out of the game in the final quarter but only for tactical reasons.
Having recorded to the club that he was feeling unwell in the days following the match, Macrae has since been moved into the AFL's mandatory concussion protocols.
Macrae was subject to a heavy tackle from West Coast's Elliot Yeo that has since seen the Eagle handed a one-game ban for a dangerous tackle that drove Macrae's head into the Marvel Stadium turf. The Dogs onballer was able to continue in the match and the incident is not suggested to be the reason for Macrae's concussion symptoms.
“Soon after the completion of the game, Jackson developed some low-level symptoms that he reported to our Club Doctor,” head of sports medicine Chris Bell said in a club update.
“Jack subsequently failed a concussion test and was immediately placed in protocols.”
“Jack will be assessed during this week before a return to play plan is developed.”
While Luke Beveridge is likely to gain star veteran Tom Liberatore for the Cats clash following his own battle with concussion, the Bulldogs will be awaiting Tuesday's Tribunal hearing to know if defender Taylor Duryea will be playing on Saturday night.
Duryea and the Dogs have decided to challenge the former Hawk's one-game suspension for rough conduct on Eagle Jamie Cripps from Round 23.
If successful at the Tribunal, Duryea will be deemed available to play, whereas if the ban stands the 32-year-old's season could be over.
The Western Bulldogs are needing a win against the reigning premiers to be any chance of booking a finals spot, with a further four points, coupled with GWS losing to Carlton, seeing Beveridge's men continue their finals streak.