NEW YORK — Washington Nationals ace Max Scherzer wanted to throw a bullpen session Friday, but for precautionary reasons, he did not. Instead, Scherzer threw lightly from flat ground at Citi Field as the long-awaited return of the right-hander stretched into another day.

“He’s progressing,” Manager Dave Martinez said. “If he feels up to it tomorrow, he might throw a bullpen. We’ll see how he feels.”

The Nationals could have used Scherzer in this series against the hottest team in baseball, the New York Mets, who have their three best starters — Marcus Stroman, Noah Syndergaard and Jacob deGrom — lined up to chip away at Washington’s lead in the NL wild-card standings. But the 35-year-old is on the injured list with a mild rhomboid muscle strain in his back, meaning the team will have to rely on its healthy big three of Stephen Strasburg, Patrick Corbin and Aníbal Sánchez.

Before the all-star break, Scherzer suffered a different back injury that forced him to withdraw from the game. Since, Scherzer has ping-ponged around the dugout while waiting to get back, with Martinez remarking on the indefatigable star “itching” to return. A reporter joked about Scherzer possibly returning for the Mets series, and a suddenly serious Martinez said, “You never know with Max.”

“We have to keep him on schedule,” Martinez said. “He wants to get back, but we got to be smart. I told him, ‘We’re going to make sure you’re right when you come back.’ ”

Until this month, Scherzer was one of the most durable pitchers of the modern era. He has made at least 30 starts each season since 2009 and struck out at least 230 batters every year since 2012. Now, at 134⅓ innings and 189 strikeouts, at least one of those stretches seems in jeopardy.

Still, the news of the setback did not concern Martinez. For him, this is about the long game.

“When he’s ready to go,” Martinez said, “we get him back for the duration.”

Nationals (61-53)

Trea Turner, SS

Adam Eaton, RF

Anthony Rendon, 3B

Juan Soto, LF

Matt Adams, 1B

Kurt Suzuki, C

Brian Dozier, 2B

Victor Robles, CF

Stephen Strasburg, RHP

Mets (59-56)

Jeff McNeil, RF

Amed Rosario, SS

Michael Conforto, CF

Pete Alonso, 1B

J.D. Davis, LF

Wilson Ramos, C

Todd Frazier, 3B

Joe Panik, 2B

Marcus Stroman, RHP