The entire season-opening three-game series between the Washington Nationals and New York Mets was called off on Friday after three players for the 2019 World Series champions tested positive for COVID-19.

The Nationals announced the postponement of games scheduled for Saturday and Sunday at Nationals Park, saying the decision was “due to continued follow-up testing and contact tracing involving members of the Nationals organization.”

The opening day game in Washington on Thursday night already had been put off, just hours before it was supposed to begin, with Max Scherzer pitching for the Nationals against Jacob deGrom of the Mets in a matchup between the recipients of a combined five Cy Young Awards.

At least three Nationals players have tested positive for COVID-19, the illness caused by the novel coronavirus.

General manager Mike Rizzo said Thursday a fourth player has been deemed a “likely positive.” He has not identified any of the players involved.

One of the players had a fever, according to Rizzo, who said the others are not showing symptoms.

Further testing and contact tracing was being done to make sure no one else might be sick or potentially was exposed.

Rizzo said the team essentially had mandated that everyone in the Nationals organization should quarantine - not just those known to be affected.

“We’re still in the midst of a pandemic, and people need to still take this seriously. Unfortunately, it hit us, and we’ve got to take care of our own now,” Nationals manager Dave Martinez said Thursday. “All I can say is: Be safe, continue to wear your masks like they ask and know that this still can happen to anyone. It’s tough for us right now, but we’re going to get through it.”

Friday originally was set up as a day off for the Nationals and Mets to allow for a makeup contest if there were an issue with Game 1, such as a rainout.

The Mets worked out at Nationals Park on Thursday, with pitchers throwing live to hitters.

“To be honest, it wasn’t a surprise. We’ve been in situations like this since last year,” Mets manager Luis Rojas said. “The health is the No. 1 thing still in the world. We’re taking care of ourselves. Everyone’s taking their mask everywhere. We’re doing everything we need to do.”