The NFL and NFL Players Association have yet to seriously consider putting players into self-contained "market bubbles" to keep its essential players and staff healthy amid COVID-19.

While saying that "all options remain on the table," NFL medical officer Allen Sills emphasized that the NFL's current plan is geared to identify infections early to prevent spread rather than toward trying to seal out the virus entirely.

Early returns from the NBA, WNBA and professional soccer indicate that bubbles work while the outbreak on the Miami Marlins of the MLB has cast doubt on the NFL's plan.

"I have a tremendous amount of respect for Dr. Sills and all the work that he and all of his colleagues at the league have put into trying to come up with the best plan that they can under the circumstances," epidemiologist Zachary Binney said. "But with that said, if you're going to call the NFL's plan a 'virtual football bubble,' then you have to call MLB's plan a 'virtual baseball bubble.' [The NFL] would have to expect that the Dolphins are going to experience a different result than the Marlins, when I think, if anything, I think it's going to be more difficult for the Dolphins because of the sheer number of people who are going to have to behave and not engage in risky behavior, as well as the additional close contact in football that doesn't exist in baseball."

In the absence of a sealed bubble, the NFL and NFLPA worked to ensure testing results within 24 hours from BioReference Laboratories, the same testing firm used by the NBA and WNBA.