LeBron James says he would refuse to play if the Los Angeles Lakers had to stage games behind closed doors because of the coronavirus outbreak.
On Friday, the NBA asked teams to start preparing for the possibility of playing without fans in attendance.
In a memo obtained by ESPN, the NBA has also asked teams to identify "essential staff" in order to limit attendees.
"Play games without the fans? No, simple answer," said James after the Lakers' win over the Milwaukee Bucks.
"I ain't playing if we haven't got the fans in the crowd, that's who I play for.
"I play for my team-mates, I play for the fans, that's what it's all about.
"If I show up to an arena and there are no fans in there, I ain't playing."
Lakers reach NBA play-offs
The Lakers' 113-103 victory over the Bucks saw them clinch a spot in the NBA play-offs for the first time since 2013.
James excelled for the Lakers with 37 points in a compelling match-up with star Bucks forward Giannis Antetokounmpo, who had 32 points.
Lakers forward Anthony Davis also hit 30 points at the Staples Center.
The sides were tied 48-48 at the half but the Lakers went on an 18-0 run before holding off a late Bucks rally.
It was a meeting between the sides with the two best records in the NBA this season, with Eastern Conference leaders Milwaukee having already claimed their play-off berth.
The defending champion Toronto Raptors have also secured an Eastern Conference play-off spot.
The Lakers are top of the Western Conference with a record of 48 wins and 13 losses from 61 games.
The last time the Lakers were in the play-offs they were beaten 4-0 in the first round by the San Antonio Spurs, with the late Kobe Bryant missing the series through injury.
The 16-time NBA champions struggled in the subsequent years, missing the play-offs last year even after three-time champion James joined.
But since acquiring Davis in a trade with the New Orleans Pelicans last summer, the Lakers have been one of the most impressive teams in the league this season as they seek to win a first title since 2010.