Watch Now: How College Football Teams Will Address COVID-19 On Injury Reports (3:17)

All signs point to the NFL pressing forward with its 2020 season amid the COVID-19 pandemic, even though nearly one-third of all teams are reportedly already dealing with positive coronavirus cases. And while some players have publicly said they're ready to risk their health to play games this season, NFL Players Association president J.C. Tretter has cautioned against a hurried return to the field, suggesting in an open letter Tuesday that many players are actually at a higher risk for damage from COVID-19.

"We are not invincible," the Cleveland Browns offensive lineman wrote, "and as recent reports have shown, we certainly aren't immune to this virus. Underlying conditions like high BMI, asthma and sleep apnea are all associated with a higher risk of developing severe symptoms and complications when infected with COVID-19. Those conditions are widespread across the league.

"NFL players are humans -- some with immuno-compromised family members or live-in elderly parents," Tretter continued. "Trust me: we want to play football. But as a union, our most important job is keep our players safe and alive. The NFLPA will fight for our most at-risk players and their families."

Tretter's remarks echo those of New Orleans Saints safety Malcolm Jenkins, who recently said he wouldn't necessarily feel comfortable returning to the field until the risk is closer to being eliminated -- not only for the sake of his own health but for that of his friends and family.

"It is the responsibility of the employer to provide a safe work environment," Tretter added in his Tuesday letter. "I encourage all workers to hold their employers accountable to high standards. More so than any other sport, the game of football is the perfect storm for virus transmission. There are protections, both short and long term, that must be agreed upon before we can safely return to work."

In the end, Tretter indicated, football may very well happen in 2020. But it almost assuredly won't happen until the NFL and NFLPA come to terms on lots more protocol about operating this season.

"I do not believe conversations about returning to work should be a race to the lowest common denominator among employees across different professions in different industries," he said. "We are all workers fighting for the same things: better pay, better benefits and better work rules. Our individual workplaces may be different, but we should support our fellow workers in pursuing gains instead of shaming them to come back to the pack. No worker should be complacent with their rights because they have what others outside their business deem 'good enough.' Instead of racing to the bottom, let's push each other to the top."