Sydney Roosters doctor Ameer Ibrahim lauded Cooper Cronk's courage in the NRL Grand Final after comparing the veteran's shoulder injury to a motorbike accident.

Cronk remarkably played with a broken scapula in the Roosters' 21-6 win over Melbourne Storm in Sunday's NRL decider at ANZ Stadium.

There were major doubts over Cronk's fitness heading into the showdown after he sustained a serious injury against South Sydney Rabbitohs in the Preliminary Final.

However, the full extent of Cronk's injury has only started to emerge, with Ibrahim taken aback by the 34-year-old's bravery.

"It's the most heroic thing I've seen from an athlete. Easily," Ibrahim said.

"It's one thing to break your bones in a game when the adrenaline carries you over the line. But to go through one and a half games - because it [occurred] halfway through the Souths game - and then come through this busted, he would have turned up [for the decider] in 11 out of 10 pain and prayed the injection worked … In 20 years, 100 per cent, I've never seen anything like it."

"It had hyperbaric chambers, cold lasers, infrared saunas - we tried everything," Ibrahim said as he revealed the lengths the Roosters went through to ensure Cronk was fit for his reunion with former side the Storm.

"Ice packs. We tried to have a hard plastic splint on the shoulder blade so we can hold it together. There's a bone-stimulator machine that helps with healing up fractures, but it takes four weeks instead of six. We didn't have four weeks, we didn't have six.

"It was interesting, everyone I'd spoken to in footy hadn't seen it. They're motorbike accidents."