Revealed: The horrific extent of internal injuries Melbourne Demons superstar Christian Petracca suffered during King's Birthday AFL showdown with Collingwood

Melbourne Demons superstar Christian Petracca will be sidelined indefinitely after scans confirmed multiple injuries - including a lacerated spleen - during a collision in his team's King's Birthday loss to Collingwood.

Petracca, 28, was taken to hospital after the game, following a marking contest late in the first quarter where he was kneed in the ribs by Collingwood captain Darcy Moore at the MCG.

He was assessed at quarter-time and was given pain relief, then bravely returned to the field before the pain became unbearable.

'This is extraordinary, Christian barely crawled off the ground at quarter-time,' footy great Tim Watson said in commentary.

Geelong legend Cameron Ling added: 'He's being so brave right now, but he's not comfortable out there at all. I don't know how much longer he can last.'

Subsequent scans revealed Petracca suffered four broken ribs, a lacerated spleen and a small puncture to his lung in the incident. 

The midfielder underwent surgery on Monday evening and remains in hospital recovering.

He took to Instagram post surgery, thanking his followers for their 'love and support.'

Demons football boss Alan Richardson stressed Petracca's health was the main priority rather than a return date.

'The next few weeks will be crucial, and we will be monitoring his progress closely to make sure he heals properly and fully,' he said.

'As his recovery progresses, we will look towards a return to play timeline.

'He's obviously an extremely important player for the team, but his health and recovery are our top priorities right now.'

Melbourne sorely missed Petracca as Collingwood secured a convincing 38-point victory on Monday in front of 84,659 fans.

Simon Goodwin's men sit in 10th spot after 13 games and are next in action when they take on the struggling Kangaroos on June 22.