North Melbourne youngster Declan Watson has suffered a suspected serious knee injury at training.
The 18-year-old was pictured going down at training on Thursday.
He was in visible pain as he clutched his left knee.
AFL.com.au reported he was sent for scans immediately after being helped from the field.
Watson has battled injury all year in his first season in the league, after being drafted with pick 34 in last year's draft.
He returned from ankle and shin problems to the VFL last weekend, playing down back and spending time on Hawthorn forward Tyrone Vickery.
"He had a really good third quarter. He did a couple of nice things in the first half and in the last as well, so it was really pleasing to see him playing to his attributes," North Melbourne development coach Gavin Brown told nmfc.com.au.
"He played on (Ty) Vickery for a bit of time and beat him in a couple of contests as well. It was really pleasing."