NFL's top doctor: There won't be "football as usual" in 2020

Dr. Allen Sills, the NFL's chief medical officer, told Axios that he's "very optimistic" about the league's season moving forward this fall — but cautioned that it won't be "football as usual."

Why it matters: "There are going to be a lot of changes in the way that we do things, from how we practice, to how we lay out our facilities, to how we travel, to how we organize sidelines and the on-field experience," he said.

His comments come after Dr. Anthony Fauci told CNN that the NFL may need a "bubble" — like the NBA's plan at Walt Disney World — in order to make this season work.

• "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," Fauci said.

The state of play: Sills said the league is using the concept of an "ecosystem" rather than a "bubble," arguing that it "encompasses the fact that it's everybody who is together with shared responsibility and shared risk."

• The "ecosystem" concept has formed the basis of the league's plan for play this year, as it tries to mitigate the risk to players, coaches and staff.
• He said that those within the "ecosystem" share a duty to "practice appropriate public health guidelines and minimize their own individual risk" to benefit the larger group.
• "It's a different concept obviously than everybody being at one single site and nobody coming in and out," he added.

The big picture: Sills also noted that the NFL has been engaged in a "very collaborative effort" with other leagues "to share learnings and source ideas from each other" on best practices to keep their employees safe.

• He believes that the league won't end the season with the same protocols put in place at the start, expecting them to "evolve and change as new knowledge becomes available."
• "If you think about how long it's been since all this started — sheltering at home, quarantining — it feels like a really long time. But it's been about 100 days, and that's roughly the same amount of time that we have between now and the start of our season," he said.

The bottom line: "One of our athletic trainers probably expressed it best when he said, 'It's not going to feel normal because it's not going to be normal.'"