MELBOURNE's ruck depth could be tested further after Jake Spencer was ruled out for the second half of the Demons' Anzac Day eve clash with Richmond at the MCG.

Already without All Australian big man Max Gawn for an extended period due to a hamstring injury, Spencer hurt the AC joint in his right shoulder in the first quarter and his right knee in the second term.

Spencer did not return to the bench after half-time along with rookie forward Tim Smith, who was taken to hospital with suspected broken ribs, leaving the Demons down to two fit players on the interchange.

The ruckman was spotted on the bench with his right arm in a sling, suggesting the injury could sideline him for multiple weeks.

Smith copped a knee to the back from Tiger defender Alex Rance midway through the second quarter and there are concerns he may have a collapsed lung.