NSW officials are hopeful Koroisau will play the full 80 minutes in Adelaide, but are also well aware he has averaged 11 minutes off the field in each club game this year.
If Koroisau needs to be rested, or is removed from the field through injury, it had widely been thought that No.14 Nicho Hynes would fill in at dummy-half.
However, the Blues are seriously considering using Luai instead.
The Penrith five-eighth spent nine minutes playing out of dummy-half on his Origin debut in Townsville in 2021, and also played hooker for Samoa at the 2017 World Cup.
Moving to hooker would also allow Hynes to act as a playmaker, with the No.14 utility training on the left edge for parts of NSW's first session on Tuesday.
Blues assistant Danny Buderus, who is arguably the state's greatest Origin hooker, nominated Luai as the chief option and said there would be no issue training him up.
"We'd like to think Api can get the 80 out, but you always cater for something that does pop up," Buderus said.
"You have Romey who can jump in there, there are different options we can look at. You just have to think about what the game needs at the time and make that decision.
"They are natural footy players, and very elite in what they do. And their skills stand alone.
"You give them a couple of real simple KPIs, and they will just run with that. They are all very elite with what they do on the field."
Cameron Murray could also be another surprise option considered by the Blues, particularly given his ability to defend in the middle of the field.
But Luai himself is also willing to make the shift, and said he would feel comfortable slotting in at hooker if required.
"I have done it before, so it is not unknown waters for myself. Whatever they think can help better the position of our team, I am happy for it," Luai told AAP.
"I was moved there in 2021 in my first game. I am capable of doing it.
"I have played a lot of it in grade too, coming off the bench in 2019 playing hooker and defending in the middle. I am comfortable with it."
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