NSW coach Laurie Daley is "quietly confident" Payne Haas will play in Wednesday's State of Origin opener.
The enforcer has sat out three consecutive Blues training sessions as he works through a quad strain sustained last week.
Haas is set to feature in a key training session on Monday, and will be given until gameday to prove his fitness.
While Daley is "confident" the 25-year-old will be ready to play, he has shared his back-up plan, with Stefano Utoikamanu set to take the potentially vacant starting prop role.
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"We'll give Payne until Wednesday to prove his fitness," the Blues coach said on Wide World of Sports.
"Our big training session is tomorrow (Monday). We're still unsure of how much Payne will do.
"But if he's not right to play, then Stefano (Utoikamanu) will come straight into the squad ... and the starting side.
"We're very comfortable with where Payne is at in his rehab at the moment.
"We think he'll make it – we think he'll be there.
"We're quietly confident, but again, until we go through the process, we're unsure of where it's going to land."
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Daley's update comes one day after NSW doctor Nathan Gibbs detailed Haas' injury status, revealing he is on track to play.
"Payne strained his VL quad, or lateral quad, not the main central quad, and they traditionally heal much quicker," Gibbs told The Sydney Morning Herald.
"Today he was able to run about 2.5km at about 70 per cent, which puts him right on track to train on Monday, then play Wednesday.
"It was really important he ran today – if he couldn’t run today, we were going to struggle to have him play. We’re confident."
NSW Blues team list: State of Origin Game I
1. Dylan Edwards
2. Brian To'o
3. Stephen Crichton
4. Latrell Mitchell
5. Zac Lomax
6. Mitchell Moses
7. Nathan Cleary
8. Mitch Barnett
9. Reece Robson
10. Payne Haas
11. Liam Martin
12. Angus Crichton
13. Isaah Yeo
14. Connor Watson
15. Spencer Leniu
16. Hudson Young
17. Max King
18. Campbell Graham
19. Stefano Utoikamanu
20. Haumole Olakau'atu