Four people in the Mets organization — including two players and a coach — tested positive for COVID-19 and were not present for the team’s home opener against the Diamondbacks on Friday.

Brandon Nimmo and Mark Canha were officially placed on the injured list Friday. Outfielder Nick Plummer and infielder Matt Reynolds were called up from Triple-A Syracuse. A source confirmed that Nimmo and Canha were absent from the Mets lineup because they tested positive for COVID, and both players are asymptomatic.

In addition to Nimmo and Canha, a coach and a staff member also tested positive for the virus.

“Obviously I know exactly what’s going on, but I have to be careful of what I say publicly just to protect people,” Mets manager Buck Showalter said. “What’s that old expression about telling truths that hurt innocent people? I just want to do the right thing.”

Any player, regardless of vaccinated status, can return earlier than 10 days if they display a negative PCR test, an MLB source confirmed. Close contacts to the four members of the Mets organization who tested positive were also tested on Friday.

Showalter said the situation for those who tested positive is day-to-day. Outfielder Travis Jankowski replaced Nimmo at center field, and Jeff McNeil led off Friday against Arizona.

“The contingency plans were put in place as early as we could, but there was somebody waiting on everybody to get out of their cars today,” Showalter said.

It is unclear whether Nimmo is vaccinated, and Canha has publicly announced he got the jab.

Canha’s wife, Marci, said in a tweet on Friday that he is doing fine and he hopes to be back on the field soon.

“We are beyond sad to miss such a special day for our family,” Marci Canha tweeted. “We’ve been looking forward to opening day at Citi Field since the day Mark and I had lunch with Billy (Eppler) and Sandy (Alderson) in Arizona this past off season.

“We’ve taken every precaution possible, we are vaccinated and boosted, all in efforts to keep our kids, our family and friends healthy, but there’s a lot out of our control now.”

WALKER AND MAY

Taijuan Walker (right shoulder bursitis) said he felt good Friday after his second straight day playing catch. He expects to throw a bullpen on Sunday, and if all goes well, Walker should make a rehab start in the minors sometime in the middle of next week.

The Mets want Walker to stretch out at least four innings in his rehab start to build up his pitch count. It is possible he will make just one rehab outing before returning to the rotation.

Showalter is hopeful Walker will spend the minimum 10 days, or close to it, on the injured list.

Trevor May (right triceps strain) said his arm felt better on Friday after a couple of days off from throwing, but it was unclear whether he was available out of the bullpen against the Diamondbacks. The Mets did not place May on the IL on Wednesday, the day he underwent an MRI, and played down a reliever in the bullpen.

SUNDAY STARTER

The Mets have yet to announce a replacement starter for Walker’s first missed outing on Sunday in the series finale against Arizona. The obvious choice would be left-hander David Peterson, who is both stretched out and he piggybacked Walker on Monday in Philly after Walker exited his start following two perfect innings. Peterson would remain on schedule if he replaced Walker in the rotation.

“Peterson is a solid option, to say the least,” Showalter said.

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