Max Scherzer walks off the field with Nationals trainer Paul Lessard on Saturday night. (John McDonnell/The Washington Post)

Max Scherzer walked into the clubhouse Sunday morning, a white sleeve extending over his right knee, backward cap on his head, a telling look on his face. Scherzer left Saturday night’s game in the fourth inning with a hamstring injury, one the team thought required an immediate MRI exam.

“[The MRI] showed exactly what we thought. Nothing major. More of a tool to help know we need to treat it,” Scherzer said. ” . . . The good news thing about this is, I can walk and run around on this. It’s not a major strain or anything, where it’s debilitating. So I’m pretty upbeat and positive about going forward here.”

Nothing about the injury and the circumstances of his departure foretold any major trouble. The injury was acute. Scherzer felt it as he extended through a change-up, the pitch on which he extends through his follow-through the most.

“I wouldn’t have come out if that was a playoff game,” said Scherzer, who at times Saturday night looked as if he would rather not have come out even though it wasn’t.

But playoff games are too near for Scherzer to wager his October for one September evening. So the Nationals pulled him out. They sent him for an MRI. Not 12 hours later, he was bouncing at his locker as if to demonstrate his relative health. And yet, he would not commit to being ready for Game 1 of the National League Division Series, which starts at Nationals Park on Friday.

“That’s tough to say right now. We’re not even 24 hours out,” Scherzer said.

What they have, something Scherzer described as a “tweak” of his hamstring, did not prevent the 33-year-old Cy Young candidate from playing his normal game of post-start catch Sunday morning. It did not stop him from jogging up the stairs beforehand. It does not, therefore, seem likely to stop him from doing much else in the next week.

The Nationals had not committed to Scherzer for Game 1 in the first place. They have the option of starting Stephen Strasburg that day if they wish, then giving Scherzer until Saturday to shore up his hamstring. Scherzer himself pointed out that he could pitch Games 2 and 5 on regular rest. Dusty Baker would admit only that the injury “probably” affects the Nationals’ playoff rotation.

“But he’s going to be fine,” Baker said. “It’s just a matter of we got to determine when that is.”

Whenever he pitches in October, Scherzer’s regular season met an unceremonious end when he walked off the mound Saturday night. But he did so as a legitimate candidate to win his second consecutive National League Cy Young Award, a case buoyed by the fact that Clayton Kershaw struggled somewhat Saturday. Scherzer is 16-6 with a 2.51 ERA, second only to Kershaw’s 2.31 mark. Hitters are hitting .178 against him, 15 points lower than their mark against anyone else. His 0.90 WHIP leads the National League. He crossed the 200-inning threshold for the fifth straight season. Despite the fact that he left four starts early due to a variety of small ailments, Scherzer’s 268 strikeouts still lead the National League.

“I’ve done such a good job of taking care of my body over the course of my career. I’ve never come out of starts, and this year, I think I’ve come out of three,” Scherzer said. “That’s frustrating for me, because I always take pride on pitching, pitching deep into games, and taking the ball every fifth day. Unfortunately, some of these injuries are out of my control right now because I’m doing everything I can to stay out there on the mound and try to be healthy.”

As of Sunday, Scherzer seemed optimistic that he will be on the mound and healthy enough for the NLDS. After another injury scare Saturday, he and the Nationals must consider that another flash of fortune in a season that has included so many others.

WASHINGTON NATIONALS (97-64)

Trea Turner SS

Bryce Harper RF

Anthony Rendon 3B

Daniel Murphy 2B

Ryan Zimmerman 1B

Jayson Werth LF

Matt Wieters C

Michael A. Taylor CF

Gio Gonzalez P

PITTSBURGH PIRATES (74-87)

Chris Bostick 2B

Starling Marte LF

Andrew McCutchen CF

Josh Bell 1B

David Freese 3B

Jordan Luplow LF

Max Moroff SS

Jacob Stallings C

Steven Brault P

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From an infinity ERA to reliable big league reliever: Austin Adams bounces back

After a 162-game walk in the park, the Nationals step onto MLB’s high wire

What’s next for The Bullpen, the beloved Nats Park destination? Not even the owner is sure.