North Melbourne can confirm first-year defender Declan Watson ruptured his ACL at training on Thursday.
The 18-year-old fell awkwardly on his left knee and was quickly attended to by medical staff.
The 194cm had his best game in the VFL for Werribee on the weekend following a long absence with ankle and shin problems.
Watson was the Kangaroos' second pick in last year's NAB AFL Draft at No.34 overall.
He is expected to miss the next 12 months.
For more NMFC injury news and the full injury list, visit the Anytime Fitness Health Hub
