MELBOURNE big men Jake Spencer and Max Gawn have been placed on the long-term injury list.

At this stage, no replacement rookie players have been upgraded.

The pair is sidelined with knee injuries.

Gawn will miss the entire 2012 season, with Spencer out for at least eight weeks.

Melbourne is set to open its NAB Cup campaign with matches against Gold Coast Suns and Brisbane Lions at Metricon Stadium on Saturday night.

Rookies are eligible to play in the NAB Cup.