• Unvaccinated NBA players for the New York Knicks, Brooklyn Nets and Golden State Warriors would have to sit out home games this season under local coronavirus rules, according to a league memo sent to teams and obtained by CNBC.
• Both New York City and San Francisco have put in place requirements that people entering a range of indoor venues including arenas and gyms must have received a Covid-19 vaccine.
• The requirements will not apply to visiting players in the two cities.
• The NBA has not mandated vaccines for players, but has done so for referees and team and arena personnel who interact with players.

Unvaccinated players for three marquee NBA teams would have to sit out home games in the upcoming season under local coronavirus restrictions.

Players on the New York Knicks, Brooklyn Nets and Golden State Warriors will have to get vaccinated to play in their home arenas unless they have a valid religious or medical exemption, the league told front offices in a Wednesday memo obtained by CNBC. The requirement will not apply to visiting players.

Both New York City and San Francisco have set rules requiring people over the age of 12 to prove they have received a Covid-19 vaccine in order to enter arenas, gyms, restaurants and other indoor venues. The rules cover team arenas and practice facilities in those cities, the NBA said.

Players in New York and San Francisco may face fines or suspensions if they refuse to get vaccinated without a valid exemption.

The NBA has not mandated Covid-19 vaccines for players. However, the league is requiring referees and team and arena personnel who will interact with players to get inoculated against the virus.

New York and San Francisco announced their vaccine requirements amid a nationwide surge in coronavirus cases sparked by the delta variant. New York requires people to have received at least one shot in order to enter covered businesses, while San Francisco asks for people to be fully vaccinated.

The NBA said the requirements for players will go into effect Sept. 13 and Oct. 13 in New York and San Francisco, respectively. The league noted that other cities around the country could consider similar vaccine rules.

NBA training camps start on Sept. 28. The season will tip off on Oct. 19. The Nets will play the defending champion Milwaukee Bucks and the Warriors will play the Los Angeles Lakers that night.

"We will continue to follow all government and league mandates," the Knicks said in a statement.

The Warriors and Nets both declined to comment.

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