LUCKLESS Melbourne rookie Aaron Nietschke has suffered yet another cruel blow with scans confirming a third ruptured ACL. 

The 20-year-old went down in the Demons' VFL practice match with Richmond on Friday and is set to miss the entire season. 

Nietschke was placed on the Demons' rookie list for 2021 having recovered from his second ACL tear in December 2019. 

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"Scans have unfortunately confirmed that Aaron has ruptured his ACL and will again miss a large portion of the year," Demons head of football Alan Richardson told Melbourne Media.

"This is absolutely devastating news for Aaron and the club, as he was preparing for the season ahead.

"Aaron is a very impressive and resilient person, his professionalism can't be questioned and the way he attacks his rehab is outstanding.

"This is really unfortunate for Aaron who was in great shape since returning from his previous knee injury.

"Unfortunately, he hasn't been able to play consistent football since he was drafted due to injury.

"We will work with Aaron and ensure all options are assessed before deciding the most appropriate treatment required to reconstruct the ACL."

Nietschke was drafted by the Demons with pick 53 in the 2018 NAB AFL Draft and is yet to make his AFL debut.