If you are familiar with the NBA, there's a lot of players and staff who are already infected, but that was during in the process or before they travel to Orlando, but there's always the risk here, so let's hope that once the league formally resume their season, there would be no more infections that will be recorded.
That will be very difficult, even if the majority of the players take the right precautions you only need a few of them to slip once or twice to get infected and if they do not show symptoms for quite some time then they could infect many players, I am pretty sure this is a nightmare scenario for the NBA and they will try to avoid it at all costs but when battling with an invisible enemy even the smallest mistake could force the NBA to shutdown again.