I expect that most states' opening up strategies include restrictions of some sort on entries of interstate travelers from areas deemed to be of high risk. e.g., after November 23, SA will allow most fully vaccinated people from interstate to enter freely (no quarantine), but will require quarantine for fully vaccinated people from Local Government Areas with "community transmission and less than 80% of the population fully vaccinated".
From the As at 24 October (https://www.health.gov.au/sites/default/files/documents/2021/10/covid-19-vaccination-local-government-area-lga-25-october-2021.pdf) the City of Sydney, Brisbane, Cairns, Launceston, Melbourne, Knox, and Perth LGAs all were below 90%. Several are more than 20% below that 90% threshold (City of Melbourne was only 62.8% fully vaccinated).
So it's possible (probable?) that there'll be times when one or more of those LGAs will be caught by the SA quarantine criteria, early in the NBL season. If that coincides with an NBL team coming from that LGA to play in Adelaide, the players and staff may be expected to quarantine. That would affect the 36ers and the teams based in those LGAs.
Presumably other states will have similar rules in place until 90% full vaccination is reached. That's when the SA rule will cease to apply. Until then, who knows how strictly they'll apply their remaining quarantine and entry rules?