North Melbourne can confirm Ed Vickers-Willis ruptured his anterior cruciate ligament (ACL) in Sunday’s loss to Fremantle.
The 22-year-old went down late in the first quarter after a marking contest.
The defender was playing his first game since Round 7 last year, when he re-injured his PCL after colliding with the post.
“We’re extremely disappointed for Ed who has worked extremely hard since his PCL injury to get back to playing footy,” North GM football Cameron Joyce said.
“He made the seamless transition back into the side throughout the JLT series and looked to be well positioned for a great season.
“He is a diligent worker and a true professional which will hold him in good stead on his road to recovery.
“For now, our primary focus is to provide him with all the support he needs.”
Vickers-Willis will meet with a surgeon in the coming days with an operation likely this week.