League sources told ESPN and NFL Media that Payton has been battling the virus for more than a week and has a few days left of quarantine. He told ESPN that he didn't start feeling symptoms until Sunday and opted to take the test Monday. He received the positive test results Thursday.
According to NFL Media, he attended a horse race Saturday at Oaklawn Park in Arkansas before his diagnosis. Payton, who has dealt with fatigue, is resting at home and said he hasn't experienced any fever or respiratory issues.
Payton, 56, becomes the first known person in the NFL to test positive for the virus. He said he came forward with the diagnosis because he wants people to listen to warnings from government officials about the COVID-19 pandemic.
"This is not just about social distancing," Payton said. "It's shutting down here for a week to two weeks. If people understand the curve, and understand the bump, we can easily work together as a country to reduce it. Take a minute to understand what the experts are saying. It's not complicated to do what they're asking of us.
"Just that type of small investment by every one of us will have a dramatic impact. I was fortunate to be in the minority, without the serious side effects that some have. I'm lucky. Younger people feel like they can handle this, but they can be a carrier to someone who can't handle it. So we all need to do our part. It's important for every one of us to do our part."
NFL commissioner Roger Goodell announced Monday night that the league and NFL Players Association agreed to indefinitely delay the start of teams' off-season programs due to the virus.
The NFL also announced Monday that the upcoming draft will proceed as scheduled at the end of April, but the draft will no longer include public events in Las Vegas.
Members of 76ers, Celtics, Lakers, Nuggets test positive
The Philadelphia 76ers announced Thursday that three members of the franchise tested positive for the coronavirus. The 76ers' statement came hours after the Denver Nuggets confirmed one positive test.
The 76ers said players, coaches and basketball operations staff were among those tested for the virus. According to the team, the three individuals who received positive test results are in self-isolation and will be monitored by medical professionals.
"Three individuals have received positive test results for COVID-19. All other test results are currently negative," the 76ers said. "We have reported this information to state and local health authorities as required. Pursuant to CDC guidelines, the individuals are in self-isolation and will be monitored closely by medical professionals.
"The health of our players, staff, fans and community is paramount, and we continue to be guided by medical experts at this time."
The Nuggets individual tested positive after experiencing symptoms Monday. According to the team's statement, the person is currently under the care of team medical staff and in self-isolation.
Neither team revealed whether the positive tests belonged to players.
Later Thursday, Boston Celtics guard Marcus Smart confirmed on social media that he tested positive for the coronavirus. Before his Twitter post, the Celtics released a statement announcing that one player tested positive.
"I'm OK, I feel fine. I don't feel any of the symptoms," Smart said. "But I can't stress enough practicing social distancing and really keeping yourself away from a large group of people and just really washing your hands and help protect yourself. And help protect others by protecting yourself."
The Lakers were prompted to test members of their team after four Brooklyn Nets players tested positive. Los Angeles' last game was against the Nets on March 10 at Staples Center.
Utah Jazz center Rudy Gobert became the first NBA player to test positive for the virus. Jazz teammate Donovan Mitchell, Nets star Kevin Durant and Detroit Pistons big man Christian Wood also had positive test results.
The NBA suspended its season after Gobert's positive test. It remains unclear when the league will attempt to resume play.
Earlier Thursday, the league sent out a memo to all 30 teams stating that players will no longer be allowed to work out at team facilities starting Friday, according to ESPN.
MLB cancels games in Mexico City and Puerto Rico
Major League Baseball announced Thursday that it has canceled games scheduled for this season in Mexico City and San Juan, Puerto Rico, because of the coronavirus pandemic.
The games will be rescheduled for the home teams' cities, according to the league. Before the cancellation, the games in Mexico City would have marked the first MLB regular-season game there.
"It breaks our heart we won't be playing in front of the incredible fans in Mexico this year, but health and safety come first," the Diamondbacks said in a statement Thursday. "We promise we'll be back soon."
MLB commissioner Rob Manfred announced Monday that opening day was delayed until the middle of May at the earliest due to the virus.