MELBOURNE draftee Aaron Nietschke will miss the entire 2019 season after rupturing the anterior cruciate ligament in his right knee at training on Friday.

Nietschke, pick No.53 in last year's NAB AFL Draft, went down with the serious knee injury in a closed training session at Casey Fields on Friday.

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"Unfortunately, scans have confirmed that Aaron has ruptured his ACL," Demons football manager Josh Mahoney told

"He will meet with the surgeon today, with the most likely option being that he will miss the year.

"This is obviously a tough time for Aaron – as a club we will ensure we put the best support around him during the rehab process, like we do for all our players."

Nietschke had been training as a defender this pre-season but is projected to turn into a midfielder in the longer term given his ability to win the ball in traffic and dispose of it effectively.

The 18-year-old was recruited from Central Districts in the SANFL and averaged 32 disposals to win the SANFL Under-18s league best and fairest award.