"It's true," Miller told 9NEWS by phone. "I've just been here in the crib, and I started to get a little cough. You know, I have asthma, and I started getting a little cough a couple days ago. My girlfriend ... she told me when I was asleep, she said my cough, it didn't sound normal."
Miller, a unanimous choice for the NFL All-Decade Team, said a nebulizer didn't help, and his assistant persuaded him to go to the doctor to get tested on Tuesday.
"It's crazy,'' Miller told 9NEWS. "I have to be quarantined here at the house. There's not really any medicine or anything like that. Dr. [Steve] Geraghty told me if my breathing changed ... honestly, I'm still new to this. This is like an hour [since learning I tested positive]. I'm not sure what's going on, but I tell you what, I'm in good spirits. I'm still Von. I'm not feeling sick or hurting or anything like that."
In a statement, the Broncos said Miller went public with his diagnosis to emphasize that anyone can be afflicted with the virus, and he remains under the care of the team's doctors.
Miller, 31, posted an Instagram story later Thursday, thanking people for their support after news of his positive test came out.
"I'm going to do whatever I have to do to get thru this!" he wrote. "Take this seriously. It's definitely FOR REAL."
Miller is the first member of the organization known to have tested positive for COVID-19, the team said, adding that its doctors are following all coronavirus treatment procedures while caring for Miller.
Miller is the second active NFL player known to have tested positive for the coronavirus. On Wednesday, Los Angeles Rams center Brian Allen told Fox Sports that he tested positive.
On April 6, Miller said during a conference call that he was in the San Francisco area to train in the weeks immediately following the season, but he returned to Colorado before the stay-at-home order in the Bay Area was announced on March 16.
"When coronavirus started going crazy, we came back,'' Miller said.
Miller was asked April 6 how he was adjusting his offseason schedule, given the restrictions of Colorado's stay-at-home guidelines. He gave no indication that he was ill, said he felt good about his offseason and said he had canceled his travel plans for the foreseeable future, including a trip to the Kentucky Derby.
"Everybody is going through the same thing. It's a tough time," Miller said. "It's a crazy time that my mom, my grandmother didn't experience, and we're experiencing it. Just trying to stay the best, stay positive. Everything I need to do, I can do here at the house."