Any return to play must also come with a green light from the N.B.A. players’ union. A spokeswoman for the union did not immediately respond to a request for comment. It is also unclear what the logistics of such a return would be, such as how many, if any, fans would be allowed into an arena for games, how freely players would be allowed to move around or what kind of testing would take place. The games would almost assuredly be run without fans in the stands, as has been the case for some other recent sporting events in golf and soccer. Any return to play would also have added risks for players or team personnel who have underlying health conditions, or for people over 65, a group that includes three head coaches.