When Major League Baseball announced on the eve of Opening Day that it would be expanding its postseason format from five to eight teams per league, the Mets did not outwardly rejoice. Their goal, after all, was a National League East title.

Still, the Mets seemed obvious beneficiaries of the rule change, considering the challenges of their division. The Braves were the defending NL East champions. The Nationals were the reigning World Series champs. The Phillies were in contention, and even the Marlins seemed improved. If the Mets were to fall short of first place, MLB’s new postseason format offered a safety net.

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The idea that they would miss out on the playoffs altogether seemed improbable, if not unthinkable, within the walls of their clubhouse. And yet when the Nationals swept the Mets in a doubleheader Saturday in Washington, that’s exactly where they stood. They dropped Game 1, 4-3, to be mathematically eliminated, then lost Game 2, 5-3 (both in seven innings). Should the Mets lose again on Sunday, they will finish the season not in the playoffs, but tied for last place.

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“Where eight teams go and we didn’t make it, that’s pretty frustrating,” Game 1 starter Jacob deGrom said. “The level of disappointment is very high.”

Rick Porcello allowed five runs (three earned) in the third inning of the nightcap after deGrom gave up three in Game 1. Neither pitcher received much benefit from his defense nor much support from his offense, which was a theme of the Mets’ season. When they pitched well, they tended not to hit. When they hit well, the pitching often struggled. Their bullpen and defense had issues throughout.

After the doubleheader, manager Luis Rojas held a team meeting to “talk about how unfortunate it is right now, to find out today that we’re not going to be playing past tomorrow.” Left fielder Dominic Smith said that once Rojas left, players talked some more among themselves. During a meeting with the media, Porcello personally apologized for his season performance.

“The guys are obviously a little bit upset,” Smith said, praising Rojas for the job he did as a rookie manager. “We know what we need to do in this offseason to come back stronger in 2021.”

Coming off a year in which they rebounded from a poor start to perform -- for a brief stretch toward the end of the summer, at least -- like one of the best teams in baseball, the Mets came into this season with high expectations. Though they ultimately fell short last September, they figured they had unlocked the key to winning more consistently in 2020.

Instead, the Mets stumbled out to another poor start, unable to string together any sort of momentum. Porcello, Michael Wacha and Steven Matz all struggled, with only Porcello retaining his rotation job all year. Due to those starting-pitching inconsistencies, the Mets never won more than three games in a row. They felt they were in the middle of breaking out with a three-game streak in late August, before a pair of positive COVID-19 tests kept them off the field for five days. When they returned, the Mets lost their first two games and never quite recovered.

“To the Mets fans, I’m sorry that we couldn’t have done better for you,” Porcello said.

“I’m not happy,” added Smith. “We had a great team going into camp and we held each other to a high standard. The playoff picture is something that we all agreed on and wanted to accomplish. For us not to accomplish that ... I’m not too happy. I probably won’t sleep too well over the offseason.”

That offseason will be full of additional uncertainty for the Mets, who have a prospective new owner in Steve Cohen, significant rotation holes and other roster areas that must be addressed. The Braves remain a young, strong and hungry team. The Marlins figure to continue improving. The Phillies have a history of spending to patch over holes. Given all that, it’s hard to predict what the future of the NL East will bring.

On Saturday, New York was still processing the present. Earlier this month, outfielder Jake Marisnick called the Mets “too talented to not make the playoffs,” which is how they all felt.

But the playoffs are no longer an option.

“I wish we had 100 more [games],” first baseman Pete Alonso said. “I feel like this team is built to win. We have just a ridiculous amount of talent. It’s unfortunate that we couldn’t put it together.”