A general view of the game between the Washington Nationals...

A general view of the game between the Washington Nationals and the Philadelphia Phillies during the ninth inning at Nationals Park on July 18, 2020 in Washington, DC. Credit: Getty Images/Scott Taetsch

WASHINGTON — It was Opening Day, and then it wasn’t.

The Mets’ first game of the season, a Thursday night matchup against the Nationals, was postponed because of the Nationals’ COVID-19 problems, MLB announced.

The teams won’t play until Saturday at the earliest — and even that is far from a given.

Nationals general manager Mike Rizzo revealed Thursday evening that the team learned of at least two and perhaps three additional positive tests, giving them a total of as many as four (including one initial positive on Wednesday). All are players. Virtually the entire team is quarantining, Rizzo said.

Hours earlier, Mets manager Luis Rojas said he was "pretty confident" they would play Saturday. But the new information provided by Rizzo "changes the landscape," a source said, leaving the Mets in limbo indefinitely.

"I wanted to see some jets flying over me today, see some flags on the field and I want to see some fans," Mets shortstop Francisco Lindor said. "So I was bummed out for sure."

The coronavirus issues are limited to the Nationals, sources said. The Mets do not have any positive tests.

Rojas said, however, that the Mets are not actively encouraging their players to get vaccinated. They did recently poll players to see how many want it when it is available to them.

"Nobody is trying to influence what decision they’re going to make about it," Rojas said.

The fate of the rest of the series is unclear, but the initial postponement came with the possibility that more would follow. A person familiar with the league’s thinking said MLB would "play the long game and be smart about it," as it did last year. For intradivision series between teams in close geographical proximity, making up games is relatively easy.

The Mets are scheduled to return to Washington for series May 18-20 and Sept. 3-6.

The teams will not play Friday, which will remain a previously scheduled off day — put there by schedule-makers to allow for an Opening Day makeup, usually in the event of bad weather.

"Out of an abundance of caution, the game will not be made up on Friday," MLB said in its news release.

In the meantime, the Mets worked out at Nationals Park on Thursday and plan to do so again Friday. Whenever their season starts, they intend to stick with the previously decided rotation: Jacob deGrom, Marcus Stroman and David Peterson.

If a game happens Saturday, it would line up deGrom to pitch the home opener on Thursday, too.