With heavy cloud overhead and rain around Sydney all day, the Scorchers have given themselves a potential advantage chasing second.
Perth have dropped to third on the BBL ladder, but have games in hand and would move into the crucial top two ahead of the Sydney Sixers with a win.
The Thunder are seventh, and would likely need to win all four of their remaining games to win the final.
Jason Behrendorff is out for the Scorchers, with spinner Hamish McKenzie coming in.
Wicketkeeper Matt Gilkes comes into the Thunder side as an extra batter, with quick Liam Hatcher making way.
SYDNEY THUNDER: Alex Hales, Cameron Bancroft, Tom Kohler-Cadmore, Matt Gilkes, Ollie Davies, Alex Ross, Daniel Sams, Nathan McAndrew, Chris Green (capt), Gurinder Sandhu, Tanveer Sangha.
PERTH SCORCHERS: Zak Crawley, Sam Whiteman, Aaron Hardie (capt), Josh Inglis, Laurie Evans, Cooper Connolly, Ashton Agar, Jhye Richardson, Andrew Tye, Hamish McKenzie, Lance Morris.
14°C