Declan Watson faces a year
out of football after rupturing the anterior cruciate ligament in his left knee at training.
Watson, 18, crumbled to the Arden St surface clutching his knee early in the session and was quickly surrounded by North Melbourne trainers.
He was able to walk from the ground with a trainer on each side of him, but was visibly distressed. The Roos' medical staff immediately sent him for scans that confirmed their worst suspicions.
"It was a really innocuous, slight change of direction and his knee buckled," Kangaroos caoch Brad Scott said.
"So it's an ACL rupture and that will be 12 months (out) for Declan after his best game at North Melbourne (in the VFL) last week, so it's bitterly disappointing for him and for the club."