The Sydney Sixers expect Sean Abbott and Moises Henriques to face the Thunder with the pair racing to get a negative COVID-19 test result back in time.
Abbott and Henriques flew into Adelaide from Melbourne on Thursday afternoon, in the last part of a congested process out of Australia's Test squad.
Despite already passing a COVID test in Victoria and being cleared to fly to South Australia, they were tested again on Thursday as per the state's border exemption rules.
Provided they receive a negative result by Friday evening, they will be released from quarantine in time to join the Sixers squad and face the Thunder.
Both will be crucial additions to the table-topping Sixers, following Nathan Lyon's withdrawal from the rest of the tournament.
Mitchell Starc also remains in significant doubt, awaiting results for a scan on his hamstring and potentially facing border challenges after flying home to Sydney.
Meanwhile the Brisbane Heat were able to get Marnus Labuschagne and Mitchell Swepson into Adelaide in time to face the Strikers on Thursday night.
The Strikers were also able to include Michael Neser and Travis Head, both of whom were desperate to get back into cricket after carrying the drinks in the Test series against India.
Australian Associated Press