Collingwood will await to learn the full extent of a knee injury to spearhead Dan McStay after the Magpies forward was unable to finish his side's thrilling one-point win over GWS.

The victory saw the minor premiers secure their place in Saturday's grand final against either Brisbane or Carlton, with Craig McRae's perfect September run continuing on Friday night in front of over 97,000 fans at the MCG.

The Magpies could be without McStay for the season decider, with the Collingwood recruit subbed out of the win over the Giants at the final break after sustaining a knee injury in the third quarter.

McStay was replaced by tactical sub Jack Ginnivan before the last term after hurting his knee, with the tall forward coming off the field and moved into the Magpies' rooms shortly after the ailment.

GWS defender Jack Buckley would roll onto McStay's leg after an attempted tackle, hampering the Pies attacker.

The club would act quickly to make their sub change, and will now be waiting to learn the extent of McStay's setback.

Collingwood WON BY 1 POINTS

The injury would sour a strong night for McStay, who would kick a team-high two goals and assist another from his five disposals and four marks - two of which were contested.

"He's gonna get scans," McRae confirmed when questioned on McStay's setback.

"I'm not sure if it's an MCL, so we'll get scans. I don't wanna put a definite decision on it but I think he might be unlucky to miss out.

"We'll wait and see. Until you know, we'll just put our arms around him and support him as best as you can. That'll play out pretty quickly I would've thought."

The Magpies will have an eight-day break before the grand final, with a potential team change on the horizon with McStay's concern, while veteran midfielder Taylor Adams will have his eyes on a return after a promising beginning to his rehabilitation from a recent hamstring injury.

Adams' untimely setback came as second-year star Nick Daicos made his return in time for the preliminary final, with the latter recovering from a knee injury sustained in Round 21.

The pair would be part of the only change for McRae's squad for the GWS encounter, with Adams' potential return to cause a selection conundrum for the final game of the season.

"That's gonna be a watch the clock. Every second is going to be needed," McRae said of Adams' chances.

"We'll push it to the line and see what we get."

Collingwood are set to provide a more extensive update on the playing status of Adams and McStay over the coming days.