Melbourne youngster Aaron Nietschke has suffered another ACL injury in pre-season, his second ACL rupture of 2019.

Nietschke was selected by the Demons with the 53rd pick of the 2018 National Draft, but went on to sustain his first knee in February.

Last Friday morning on the same knee, Nietschke re-injured his right knee, and will now miss the entire 2020 season, according to Melbourne's General Manager of Football Operations.

“Unfortunately, scans have confirmed that Aaron has ruptured his ACL graft, which will likely sideline him for the 2020 season,” Josh Mahoney told Melbourne Media.

“This is obviously incredibly disappointing news for Aaron and the whole team.

“He had really attacked his rehab and was in great shape prior to this incident.”

Mahoney said the club would continue to support Nietschke through his second rehabilitation, and confirmed he would have his deal extended into 2021 in a bid to allow him the opportunity to prove himself when fit.

“He’s a good young character who has shown a lot of resilience during his first year at the club and we have no doubt he will get through this again, giving himself the best chance to be available for our AFL team,” Mahoney added.

“It’s really unfortunate that Aaron hasn’t had the chance to play any footy since joining the club, but we will continue to support him in his rehab and look forward to seeing him at his best in the future.”