Games against the Detroit Pistons on Tuesday and the Toronto Raptors on Thursday are off, the NBA said.
The NBA postponed 31 games because of Covid-19 last season.
The NHL - North America's elite ice hockey league - has also called off the next three games of the Calgary Flames because of a Covid-19 outbreak.
Six players and one staff member have entered Covid-19 protocols and the NHL said there was a "likelihood of additional positive cases in the coming days."