The Dragons confirmed on Friday evening that the 27-year-old had also suffered ligament damage to his right shoulder and would be out for an "indefinite period" after his scans were assessed.

He is likely to join twin brother Josh as a Blues casualty for the rest of the series after Josh's Bulldogs said he would miss six to eight weeks with a knee injury.

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While Brett's return to the field is shrouded in uncertainty, he is resigned to missing NSW's attempt to end Queensland's eight-year Origin dynasty.

Morris Tweeted: "Absolutely devastated with the results from the scans. Shattered to miss games 2 & 3 of origin and plenty of games for the Red V. #gotheblues"

Morris produced a miraculous try-saving tackle on opposite Darius Boyd with less than five minutes to go at Suncorp Stadium on Wednesday night, despite his obvious discomfort.

He originally hurt his shoulder - the one reconstructed early in his career - as he scored the Blues' opening try. He received pain-killing injections at half-time.

Teammates later hailed his effort as one of the most memorable in Origin history, but it has come at a cost.

After the match, Morris said: "I think the biggest thing is we play a team sport and you don't want to let the boys down.

"It's just a matter of toughing it out, and if I could do my job to the best of my ability the way I was, that would help them out."

The news is also a bitter blow for caretaker St George Illawarra coach Paul McGregor, who is just about to welcome back another international winger, Jason Nightingale, from a knee injury.

"He did well to battle on through that injury," Nightingale said. "I thought he was going to come off when he did it and I didn't expect to him play on a five-day turnaround with that sort of injury.

"Now Mary [coach Paul McGregor] has got a decision to make and he'll use [our sessions for the rest of the week] to help with the decision he's got to make."

Nathan Green and Charly Runciman are both in line to be called into the Dragons's squad for Monday night's crucial clash with the Rabbitohs.

One beneficiary of Morris's misfortune is likely to be Peter Mata'utia, who only made his St George Illawarra debut in the Dragons's hiding at the hands of Parramatta.

He is likely to cement a permanent spot on the wing or in the centres.

Dylan Farrell (pectoral) is another outside back unavailable long term.

"I've watched him since he was little and he was inspiring on Wednesday night," Mata'utia said. "It's a big spot to fill, but we've got quality players to fill it."

The ex-Newcastle utility said he was grateful for axed Dragons coach Steve Price, who lured him to the club and handed him an NRL start, in what turned out to be his last game in charge. It was Mata'utia's first start in the top grade in more than two years.

"It's been a pretty upsetting week from the start and we have a job to do," Mata'utia said.

"It's not good to see anyone lose their job like that.

"He's been giving us a text saying, 'Just play good, keep moving forward and do what you need to do'.

"He was chasing me there for a while and he gave me my first chance last week in the Red V.

"I texted him and said I'm very humble for what he did for me."