Dr. Anthony Fauci is not convinced there will be a 2020 NFL season the way it is currently scheduled with the coronavirus pandemic still prevalent.
The NFL's chief medical officer, however, says the league could alter the way it is planned.
Players are scheduled to arrive in training camps in another month, and the season is set to kick off on September 10, with the defending Super Bowl champion Kansas City Chiefs hosting the Houston Texans.
The season is then set to proceed with the normal travel schedule as all games are slated to take place in each team’s own stadiums without fans.
Fauci, the director of the National Institute of Allergy and Infectious Diseases, is not sold on that plan.
"Unless players are essentially in a bubble - insulated from the community and they are tested nearly every day - it would be very hard to see how football is able to be played this fall," Fauci said Thursday on CNN. "If there is a second wave, which is certainly a possibility and which would be complicated by the predictable flu season, football may not happen this year."
MORE: What to know about the NFL and coronavirus in 2020
The NBA is resuming with a “bubble” of 22 teams converging on the Walt Disney Resort near Orlando next month. All games will be played there, and the players will be tested regularly and must adhere to strict physical distancing and mask-wearing policies.
NFL chief medical officer Dr. Allen Sills responded to Fauci’s comments later on Thursday, saying the league is addressing safety concerns and is open to changes.
"Dr. Fauci has identified the important health and safety issues we and the NFL Players Association, together with our joint medical advisors, are addressing to mitigate the health risk to players, coaches, and other essential personnel," Sills said in a statement.
"Make no mistake, this is no easy task. We will make adjustments as necessary to meet the public health environment as we prepare to play the 2020 season as scheduled with increased protocols and safety measures for all players, personnel, and attendees. We will be flexible and adaptable in this environment to adjust to the virus as needed."
One major obstacle for the NFL is dealing with the spread of the coronavirus within a sport that involves constant contact among humans. Sills acknowledged last month that with all the physical contact, there will be positive tests of COVID-19 among players.
Both Fauci and Sills' remarks came one day after Denver Broncos safety Kareem Jackson became the latest NFL player to test positive for the coronavirus.