Von Miller, the Denver Broncos’ All-Pro linebacker and the winner of the Most Valuable Player Award in Super Bowl 50, on Thursday became the latest and most prominent N.F.L. player to reveal publicly that he had tested positive for the coronavirus.

“I was shocked,” Miller said on Friday in an interview on NBC’s “Today” show. “It all started with just a simple cough and it got worse. I also have asthma.”

When his cough did not go away after several days, Miller was tested for the virus and found out two days later that its result was positive.

Miller, 31, said that he had been training in San Francisco before being diagnosed, but after stay-at-home orders were issued there, he returned to his home in Denver about four weeks ago.

“Within that four weeks, I probably left the house four times,” Miller said. “With all of those four times, I never got out of the car — just drive to pick up food and come back home.” Though he added that workers maintaining his house had been

Miller, the second overall pick in the 2011 draft, has been selected to the Pro Bowl eight out of his nine years in the league.

Miller said the N.F.L. should use caution when deciding when to play games, even if they are in empty stadium. “We shouldn’t move too fast, just do whatever is safe,” he said. “Whatever is safe that would always be our first precaution, to do whatever is safe whatever we have to do to get things back to normal, that’s what we should do.”

Miller’s diagnosis, which was first reported by NFL Network, was revealed on Thursday, a day after Brian Allen, a center for the Los Angeles Rams, became the first active N.F.L. player to publicly acknowledge he had tested positive for the virus. Through the team, Allen said he was feeling well and was not in the hospital.

Allen, 24, is entering his third year in the league, and is the Rams’ starting center. He attended Michigan State. He joins New Orleans Saints Coach Sean Payton as major N.F.L. figures who have tested positive for coronavirus.

Allen reported experiencing some symptoms of the virus, including the loss of his sense of taste and smell, as far back as three weeks ago. “I lost all sense of smell to the point where I had smelling salts here, I cracked them open, put them to my nose and nothing happened,” he told Fox Sports. “All I could feel was texture in my mouth — literally, it was the only sense I had.”

Allen had been rehabilitating from an injury at the team’s training facility in Thousand Oaks, Calif., when the positive test came in a few weeks ago. Coach Sean McVay said that after the test, the Rams closed the facility, in accordance with a leaguewide shutdown mandated by the N.F.L. In a memo sent to teams on March 24, Commissioner Roger Goodell ordered that teams close their buildings to all but essential workers until April 8. The Los Angeles Times reported that it had since reopened on a limited basis.

The Rams had previously declined to answer questions about whether anyone with the organization had tested positive, citing privacy concerns.

Based on public statements about the coronavirus, the N.B.A. has been the hardest hit North American league, with several players testing positive. The first confirmed case was the Utah Jazz’s Rudy Gobert, who drew criticism because he had earlier made light of the virus by touching reporters’ notebooks and microphones. His teammate Donovan Mitchell also tested positive, followed by Kevin Durant of the Nets, Marcus Smart of the Boston Celtics and several other players, not all of whom were publicly named.

Sydney Wiese of the Los Angeles Sparks was the first W.N.B.A. player to confirm a positive test. Like Allen, she lost her sense of taste and smell, although she said last week that she had recovered.

The sprawling world of soccer has tens of thousands of international athletes and, unsurprisingly, its share of coronavirus cases. Paulo Dybala of Juventus, Callum Hudson-Odoi of Chelsea and Arsenal Manager Mikel Arteta are among the highest-profile names to have confirmed positive tests.

While no M.L.B. players are known to have tested positive, the Yankees announced that two unidentified minor leaguers in their system had.