YOUNG Collingwood forward Harvey Harrison requires a knee reconstruction after rupturing his anterior cruciate ligament on Friday.
Scans on Saturday afternoon confirmed the club's initial fears, following an injury in the VFL.
The 20-year-old came from the ground early in the loss to Sydney's reserves at Tramway Oval and returned to Melbourne on Saturday with the team.
Harrison has shown glimpses of his potential in 2024, playing 12 games between Anzac Day and round 20, after playing four in his debut season last year.
The South Australian now faces up to 12 months on the sidelines.
Harrison will meet with a surgeon next week and is expected to undergo surgery this month.