Pendlebury went down in the opening minutes of the first quarter when he was tackled with his leg caught under Sydney’s Ryan O’Keefe.
The 21-year-old was immediately taken to the rooms and returned to the bench during the second quarter.
"He sustained a strain to his medial-ligament", chief of football Geoff Walsh told collingwoodfc.com.au on Monday.
"He won't have any scans. The doctors will treat the scans symptomatically. We think at this stage the best case scenario is he will only miss one week."
Pendlebury has been one of the most consistent Magpies this season averaging 31 disposals and six marks a game before Saturday night.
Even without registering a disposal in Saturday’s match, Pendlebury is seventh in the competition in total disposals (336).
Earlier this year Pendlebury spoke with collingwoodfc.com.au about his new found determination to become a better player in just his fourth season of senior footy.
“I spend a lot of time in the midfield and I just wanted to be a lot stronger around the contest and win a lot more contested footy than what I had in the past,” he said.
John Anthony (hip) is likely to be fit to take on Freo this weekend while Nathan Brown – a late withdrawal on Saturday with a knee injury – is also in the mix to return.
“Browny was close, he just pulled up a bit sore after the training session on Friday,” Walsh said.
“He’ll certainly be available [to play Fremantle].”
Young forward Brent Macaffer, who injured a knee in the VFL more than a week ago, will be forced to spend some time on the sidelines.
The news could be far worse for Macaffer after he suffered a partial tear to an anterior cruciate ligament, but the Pies are confident he won’t need an operation.
“I would think Brent will certainly miss another two weeks,” Walsh said.
“It’s something that’s responding pretty well to treatment. There’s a couple of guys sort of playing in the AFL with partial tears now, [Western Bulldogs Daniel] Giansiracusa being one that springs to mind.
“So it’s just a matter of him regaining the stability and getting the swelling down and then we’ll go from there.”
