New York Mets manager Luis Rojas can visualize a day in the not-too-distant future in which he is finally able to write out his optimal lineup card.

That day will not be Saturday, when a New York team coming off its most anemic back-to-back games of the season will have to figure out a way to generate runs in a doubleheader.

The Mets will look to snap a 21-inning scoreless streak Saturday, when they visit the Washington Nationals in a day-night doubleheader.

The opener will pit the Mets' David Peterson (2-5, 5.60 ERA) against the Nationals' Joe Ross (2-6, 4.19 ERA). New York hadn't announced a starter for the second game, but Washington is slated to send left-hander Jon Lester (0-2, 4.09 ERA) to the mound.

The Nationals earned a walk-off 1-0 win in the series opener Friday, when Yan Gomes delivered the game-winning single with no outs in the bottom of the ninth.

The Mets were blanked on two hits for the second straight game. They fell 2-0 to the visiting Chicago Cubs on Thursday night.

Help is on the way for the Mets, who are expected to activate second baseman Jeff McNeil (left hamstring strain) for Monday's doubleheader against the Atlanta Braves and right fielder Michael Conforto (right hamstring strain) sometime next week. Center fielder Brandon Nimmo (left hand) could begin a rehab assignment within days.

However, on Saturday, Rojas will need "The ReplaceMets" to find the form they displayed earlier this month. New York scored at least three runs in 13 of its first 14 games in June, a span in which it went 9-5.

"This group of guys has played their butts off," Rojas said. "You can't just go away from this group that easy and say, 'OK, guys are on their way, we're going to get our offense going.' I think these guys can hit. They scored the runs that we needed to win several times. That's why we've been playing solid baseball."

The Nationals have won a season-high five straight games and are 7-2 dating back to June 9, a surge built on solid pitching. Over the past nine games, Washington has allowed just 14 runs -- half of which were surrendered in a 9-7 win over the Tampa Bay Rays on June 9.

The shutout Friday -- fueled by seven innings from starter Erick Fedde -- was the third in the past seven games for the Nationals, who are 31-35 and the closest to .500 they've been since May 27.

"Everyone's excited right now," Nationals manager Davey Martinez said. "Guys come out of the bullpen throwing strikes. Starting pitching -- Fedde, what an unbelievable job that he did for us today. We've just got to keep going."

Peterson earned a win Monday, when he allowed just one hit over six scoreless innings as the Mets beat the Cubs 5-2.

Ross recorded a victory Sunday, when he surrendered five hits over eight scoreless innings as Washington beat the San Francisco Giants 5-0.

Lester didn't factor into the decision Monday after giving up two runs over 5 1/3 innings in the Nationals' 3-2 win over the Pittsburgh Pirates.

Peterson is 2-0 with an 0.75 ERA in two career starts against the Nationals. Ross is 3-4 with a 5.27 ERA in 13 games (nine starts) against New York. Lester is 7-1 with a 3.20 ERA in 10 regular-season starts against the Mets.