Coach Laurie Daley announced on Tuesday morning that Mitchell Moses would start in the halves next to Nathan Cleary, despite a hamstring injury that clouded his availability.
But the biggest shock is the omission of in-form Olakau'atu, who drops out to pave the way for Newcastle second-rower Lucas to start next to Hudson Young.
Olakau'atu is the new 20th man, the extended squad role filled by Lucas in the victorious series opener.
After being named in the squad on Sunday night, Canterbury captain Stephen Crichton drops out with a shoulder injury and will be replaced by Mark Nawaqanitawase.
Penrith's Casey McLean will take Crichton's place in the centres after impressing on debut in game one, with rugby-bound Nawaqanitawase listed on the bench.
Tolu Koula holds his spot on the wing.
Moses' return to the starting side pushes Canberra wunderkind Ethan Strange to the bench, after he starred as 11th-hour replacement at five-eighth in game one.
Parramatta captain Moses missed the Eels' last game before team selection on Monday.
But the NRL club had been confident he would recover from the hamstring injury he suffered in game-one camp in time to line up at the MCG if selected.
Superstar Brisbane prop Payne Haas comes back into the starting side as expected after missing the series opener with a knee issue.
His inclusion pushes Addin Fonua-Blake to the bench.
Four-time Blues representative Api Koroisau will start from the bench after being recalled in place of injured back-up hooker Blayke Brailey.
NSW TEAM:
1. James Tedesco 2. Brian To'o 3. Casey McLean 4. Kotoni Staggs 5. Tolu Koula 6. Mitchell Moses 7. Nathan Cleary 8. Payne Haas 9. Reece Robson 10. Mitch Barnett 11. Hudson Young 12. Dylan Lucas 13. Isaah Yeo (capt) 14. Cameron Murray 15. Victor Radley 16. Addin Fonua-Blake 17. Api Koroisau 18. Ethan Strange 19. Mark Nawaqanitawase 20. Haumole Olakau'atu.
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