WASHINGTON — By the time the Mets depart the nation’s capital Sunday night, they will have spent six days in this city without playing a game.

Such was the reality Friday after MLB, citing the need for follow-up testing and contact tracing, postponed the remainder of the Mets-Nationals series, which had been scheduled for this weekend. Thursday’s opener was postponed after positive COVID-19 tests surfaced within the Nationals organization.

Monday night is the new scheduled opener for the Mets, with Jacob deGrom slated to get the ball in Philadelphia. The Mets worked out at Nationals Park on Friday and plan to continue holding sessions there through the weekend.

J.D. Davis called the situation “a little disappointing,” but said he doesn’t blame the Nationals.

“It is unfortunate, but it can happen to anybody, guys including myself,” Davis said. “We were super-pumped for Opening Day. We’re just kicking back and waiting for an opportunity and getting word when we are going to play.”

The Nationals had four players test positive for the virus in recent days. Six other people with the organization — five players and a staff member — have been quarantined.

Last season, the Mets had a five-day layoff in August after Tomas Nido and third-base coach Gary DiSarcina tested positive for the virus. Davis noted that situation was different in that the Mets weren’t allowed to work out during that layoff.

The challenge has been keeping sharp. The Mets last played a game on Monday in Jupiter, Fla., to complete the exhibition season. On Friday, they played a simulated game, getting David Peterson on the mound. The lefty is scheduled to start Wednesday against the Phillies. Meanwhile, deGrom is expected to throw a side session Saturday as a tune-up for the opener.

“Jake is a pro and I don’t think it’s the first time he has gone through something like this as far as a holdup,” manager Luis Rojas said. “It will take a couple of extra days before he makes his start so he’ll know how to go about it and be ready Monday.”

Rojas said various options were discussed for Saturday and Sunday — including heading to Philadelphia or returning to New York — but ultimately the decision was reached to stay, with Nationals Park available for workouts.

As much as Rojas was amped about starting the season Thursday, he said there is no use lamenting about the situation.

“We have been living like this since last year and the best we can do is react quickly and start planning on what you can do to keep moving forward,” Rojas said. “I think we did that. We got together and we created the opportunity of working out and getting prepared against the Phillies, that is the focus right now.”

With the Mets and Nationals scheduled to play 19 times within the NL East and the two home cities so close geographically, MLB is comfortable there won’t be issues scheduling makeups.

Davis was asked about outcry on social media that the Nationals should have been forced to forfeit the three games.

“It would be nice to walk out of here with three wins after today, that would be pretty cool,” Davis said. “But it could happen to anybody. Being in the situation of traveling from Florida to here, I think that was kind of the exposure. I feel for the Nationals over there. It happened to them last year and then it happened to them the next year. I know nobody really wants to be in this situation and nobody really wants to be that guy that gets it and has that guy spread it. I feel [the fans’] disappointment. It was a punch to the stomach.”