Melbourne young gun Christian Petracca will miss the entire 2015 season after the prized No.2 draft pick ruptured an anterior cruciate ligament at training on Monday.

The 19-year-old was sent for scans after the training mishap, which confirmed the worst-case scenario.

“Christian had an incident today at training, which involved twisting his knee,” Melbourne football manager Josh Mahoney told the club’s website.

“Unfortunately scans today confirmed a rupture of the ACL in his left knee.

“This is devastating news for Christian and the club, as he was preparing for the season ahead.

“He’ll meet surgeons tonight and have the appropriate surgery to repair the ACL as soon as possible.”