The NBA anticipates that all of its teams' arenas will once again be able to host fans at full capacity in 2021-22, sources told ESPN's Baxter Holmes.

The league is also reportedly hopeful more fans will be allowed to return to arenas this season thanks to rising vaccination rates and widespread COVID-19 testing.

Part of the reason for the league's reported optimism is a multi-year partnership with Clear, a biometric screening company with an application that allows fans to use their phones to answer COVID-19 health surveys and provide vaccination records; the information provided helps determine whether an individual is eligible to enter an NBA venue.

The app provides arena staff with a final determination on whether a fan can enter and does not disclose individuals' private health information, according to a Clear spokesperson.

Use of the Clear app reportedly won't be mandatory for all 30 teams. One-third of the league's clubs apparently use the service already.

A majority of NBA teams have begun allowing some in-arena spectators this season, but attendance has been limited to small percentages of arenas' full capacities.