NEW YORK -- Brandon Nimmo had no inkling that he might test positive for COVID-19 until the moment that he did. At around 8:30 a.m. on Friday before the Mets’ home opener, Nimmo arrived at Citi Field to find medical staffers intercepting players on their way in.

The team had learned the previous night that a physical therapist tested positive for the coronavirus, necessitating tests for everyone. Nimmo, despite being asymptomatic, returned a positive test. So did fellow outfielder Mark Canha, bench coach Glenn Sherlock and others in the organization.

But four days later, Nimmo was back on the field, having delivered the test results necessary to re-enter the clubhouse. He appeared as a defensive replacement -- and scored the winning run -- in Game 1 of the Mets’ doubleheader sweep of the Giants on Tuesday, then went 0-for-3 with a walk in Game 2.

“I’m just very glad to be done with it and back now,” Nimmo said afterward.

Although Nimmo does not know how he contracted the virus, he said he worked last week in Philadelphia with the physical therapist who tested positive. Nimmo, who hit home runs in consecutive games before his positive test, added that he was “very frustrated,” because he demonstrated no symptoms.

“I was just trying to do whatever I could, a bunch of water and fluids -- whatever I could to try to flush it out of the system,” he said.

After delivering multiple tests with a CT value (the measure used to estimate the amount of viral material in a test sample) over 30, which indicates a relatively low presence of the disease, Nimmo tested negative for the first time on Tuesday afternoon. Those combined results satisfied Major League Baseball protocols, allowing the Mets to petition to have Nimmo activated before Game 1 of the doubleheader.

Following Game 2, Nimmo declined to say whether he is vaccinated, noting that “it doesn’t matter whether you’re vaccinated or unvaccinated” given the testing rules in place for players to return. (The procedure is now the same for all players, with no minimum stay on the COVID-19 injured list.) Asked if his experience changed any of his thoughts regarding the virus, Nimmo replied, “No. For me, I was asymptomatic the whole time. So the more frustrating part was I had already played through more painful stuff, more aches and pains then what I was feeling when I had to sit out. That was the frustrating part, but I’m just glad that we’re done, and I don’t have to test again for three months.”

The Mets are still without Canha, whose wife posted on social media that he is vaccinated. Manager Buck Showalter, who will miss Wednesday’s game due to a medical procedure, indicated that Canha is close to a return. The Mets also hope to have Sherlock back on Wednesday, which would allow him to serve as interim manager during Showalter’s one-game absence.