WASHINGTON -- The Nationals' and Mets' 2021 season opener at Nationals Park on Thursday night was postponed because of ongoing contact tracing within the Nats organization following the positive COVID-19 test result of a player on Wednesday.

Further testing resulted in two additional positive cases on Thursday, bringing the total to three Nationals players. Additionally, an inconclusive test is considered a likely positive and the person was retested. Those players already were in quarantine for contact tracing. One experienced a fever, and the others have been asymptomatic.

“We don’t want this thing to spread any further,” Nationals general manager Mike Rizzo said Thursday night. “We want to make sure that everybody’s healthy.”

The positive result on the Nats stemmed from a test conducted on Monday, the final day of Spring Training. The Nationals did not have any positive results during camp leading up to then. That night, the team flew on a charter flight to Washington.

“It’s a shame that we can’t play today, but we need to stay positive,” Nationals manager Dave Martinez said. “I’ve talked to a lot of players, and my concern is about their health and safety. … We’re going to get through this -- this isn’t the first time we’ve been through some bumpy roads. We’ve been there, and we’re going to come back from this and we’re going to play baseball.”

Citing an “abundance of caution,” the game will not be made up on Friday, an off-day. The next scheduled game of the series is Saturday at 4:05 p.m. ET, and it remains to be determined if that will be held as the Nationals conduct contact tracing of the new positive cases. Major League Baseball’s health and safety protocols include a 10-day quarantine for a positive case, and seven days for a close contact.

“This game teaches us that there's just a lot of uncertainty,” said Mets manager Luis Rojas, whose team had four games postponed because of COVID-19 last season. “At the same time, what we've gone through since last year, I think that we're pretty open-minded that things like this can happen. Right now, our sympathies are with the team on the other side, with the Nationals, that things are contained and that everyone's safe. And then secondly, that we can play on Saturday. So we'll be ready."

Rizzo said the entire Nationals team is under “Mike Rizzo-mandated quarantine until we get this thing figured out.” They are not reporting to the ballpark, and they were encouraged by Martinez to stay loose as much as they can if they have a yard or a space to do so.

The Mets held a team workout at Nats Park on Thursday afternoon. Edwin Díaz threw live BP, and Trevor May and Dellin Betances were among those who threw a side session.

"Man, I was bummed out because I wanted this one,” said Mets shortstop Francisco Lindor, whose 10-year extension with the club was announced on Thursday. “I wanted to play. I know we're going to have an Opening Day. I know we will. It’s just a matter of when. … I wanted to see some jets flying over me today. I wanted to see some flags out on the field. And I wanted to see some fans, man. I wanted to see some fans. Yeah, I was bummed out, for sure."

Both teams are making adjustments as information develops. The Mets announced Jacob deGrom will start both Opening Day and the club’s home opener (April 8 vs. the Marlins), a game that previously had been tabbed for Marcus Stroman. The Nationals are awaiting the results of the latest contact tracing before making roster moves. They are planning to make callups from the alternate training site in Fredericksburg, Va., where all the players have tested negative.

“I think this virus is a deadly virus, and we’re trying to do everything we can to protect our players and their families and our staff and the fans and the citizens of the DMV,” Rizzo said. “I think to err on the side of caution is the right thing to do.”