Stephen Strasburg pitched six scoreless innings in the Nationals’ 2-1 win over the Marlins. (Mike Ehrmann/Getty Images)

In the sixth inning of the Washington Nationals2-1 win Tuesday over the Miami Marlins, Stephen Strasburg fell behind Giancarlo Stanton 3-0. Strasburg was also experiencing calf cramps at the time, a minor problem he cannot seem to shake, and it all combined to create a rather discouraging set of circumstances for the Nationals right-hander.

But Strasburg fought back into the count against the man on a mighty home run tear and induced a groundout. He then struck out Christian Yelich on his way to completing his 26th consecutive scoreless inning — all while leaping awkwardly off the mound after every pitch, bitten by a cramp in his calf that eventually forced him from the game.

No Nationals pitcher has ever had a scoreless streak as long as Strasburg’s 26 innings. No homegrown Nationals pitcher has been as consistently dominant as Strasburg has been when he is healthy — or even when he is not-quite-healthy, as he was Tuesday night.

“It just seems like I lose a lot of fluids. It doesn’t matter how much I drink, it just kind of goes right through me,” Strasburg said. “IVs were seeming to help me in the past, but they weren’t willing to give me one here. That’s just part of it. You have to find a way, and I went as long as I could.”

Strasburg exited after the sixth after cramps left him wincing for two innings. By then, his ERA had fallen to 2.78, fourth lowest in the National League behind Clayton Kershaw and Nationals teammates Max Scherzer and Gio Gonzalez. Neither Strasburg nor his manager nor anyone else seems particularly worried about the calf cramps moving forward.

“He threw the ball great. It just came up again,” Nationals Manager Dusty Baker said. “I don’t know what to make of it, because our trainers are working on it. . . . I’m not a doctor.”

While Baker avoids amateur diagnoses whenever possible, he was candid about Strasburg’s importance to his team before the game. If the Nationals had had the right-hander last October, Baker said, things might have gone differently.

As Strasburg showed Tuesday, and in the shutout he threw in his last start, he could make a massive difference in the playoffs this time around. Thanks in part to Strasburg’s efforts Tuesday, the Nationals’ magic number to clinch the National League East title is eight.

Many teams with big division leads spend September researching their rosters, if not to see what might work best in October then to see what they might have next April.

When it comes to next season, the Nationals do not have to do much investigating, in part because Strasburg is one of four starters returning to their rotation. Their whole starting infield returns, too. Jayson Werth is not under contract, but if he does not return, Adam Eaton, Michael A. Taylor and Bryce Harper will comprise a familiar trio in the outfield.

So the Nationals’ biggest uncertainty this offseason surrounds their catchers, because Matt Wieters and Jose Lobaton can both become free agents this winter.

Pedro Severino or Raudy Read, the two young catchers the Nationals called up this September, could therefore be battling for big league jobs. Starting in place of the banged-up Wieters on Tuesday, Severino went 2 for 4 and is now hitting .319 in 28 major league games. His first hit was an RBI single in the second inning that drove home the only run the Nationals would score until Daniel Murphy homered in the eighth.

“[Severino] had a great chance to make this club out of spring training, except that he had a bad arm at the time,” Baker said. “. . . He brings a lot of energy to the team and the field.”

Severino helped Strasburg through five scoreless innings to begin the evening. But in the fifth, Strasburg began hopping off the mound awkwardly after delivering pitches, the same kind of awkward hops produced by calf cramps two starts ago in Houston.

When pitching coach Mike Maddux and trainer Paul Lessard visited the mound, Strasburg tried to wave them off, then seemed to tell them he could stay in the game. He finished the inning, then headed straight into the clubhouse before working through the heart of the Marlins’ order in that sixth inning, his last of the day before Baker decided not to risk further injury.

“I mean if he be 100 percent good, I think he throws like eight or nine innings today. He go to complete game again,” Severino said. “. . . I give him respect because nobody do in that situation — hurt their [calf] and want to keep pitching.”

Strasburg finished with eight strikeouts in six innings having thrown 90 pitches, 59 for strikes. The Nationals led by just one at the time of his departure, then by two after Murphy’s homer.

Monday, as the Nationals won by five, Baker called on his big three of Brandon Kintzler, Ryan Madson and Sean Doolittle to pitch an inning each. Tuesday, Baker stayed away from Kintzler and Madson despite the save situation, so as not to overwork them.

Sammy Solis and Matt Albers combined to throw two scoreless innings before Baker went to Doolittle in the ninth, and the left-hander worked around an unearned run to ensure Strasburg earned his 12th win.

Strasburg has now allowed two runs in 27 innings, struck out 31 and walked three since returning from the nerve impingement that caused him forearm tightness this summer. In two of his four starts since, Strasburg has battled those calf cramps, something he and the Nationals can ill afford to have disrupt outings in October. Even with those cramps, he compiled the longest scoreless streak in team history. The Nationals just need to get him to the playoffs intact.