Nationals left fielder Howie Kendrick scores in the sixth inning of the Phillies’ 5-4 win at Nationals Park on Saturday night. (Brad Mills/USA Today Sports)

The youngest player to play in the major leagues this year should have walked when he came to the plate with two outs and the tying run on second in the bottom of the ninth Saturday evening. Victor Robles didn’t get the call, and he instead found himself with a full count in his second major league at-bat.

As he stepped back in for the decisive pitch, the out-of-town scoreboard in right field at Nationals Park showed the Atlanta Braves rallying against the Miami Marlins, and the Colorado Rockies seizing an early lead over the sputtering Los Angeles Dodgers. The crowd rose to its feet, hoping Robles could produce the kind of moment that foretells stardom — or, at least, that he could tie the game against the Philadelphia Phillies and help the Washington Nationals shrink their magic number by one more.

In the end, Robles grounded out to finish a 5-4 loss, nipped by a step on a routine groundball to short that doesn’t usually create such a close encounter. But the whole thing amounted to a downright dramatic moment for a team that has fended off real drama with a steady and consistent march to the top of the National League East. The Marlins ended up losing on a walk-off walk. The Nationals’ magic number entering Sunday is two. It could all be over then.

“It doesn’t change anything because it’s inevitable,” Nationals Manager Dusty Baker said. “. . . We just have to go out and play.”

So much of the Nationals’ season has been, in effect, a foregone conclusion. Moments of excitement punctuated what has been a season almost entirely devoid of suspense. The moment they lost a National League Division Series last October, they once again became the favorites to win a largely rebuilding NL East. They never invited many doubts.

But Saturday, they woke up with a new opportunity dangling in the distance. The Nationals began the evening just five games behind the once untouchable Dodgers for the best record in baseball. As they finalize their division title, the Nationals could still improve their position further.

“We’ll just come out and play the game,” said Michael A. Taylor, who went 2 for 3 with a homer. “You can’t think about those things or you’ll start pressing and stuff like that.”

These September games were always going to mean something, however comfortable the Nationals’ position in the standings. Individuals seek stats or secure futures. Milestones linger, and less than a month remains until everyone must discover their rhythm at the plate — lest they be doomed to an October without it.

Right-hander Edwin Jackson, for example, needs a good September. He will be a free agent at the end of this season, and the Nationals could use some insurance at the back end of the rotation next year, and many teams could use a veteran with the 3.62 ERA Jackson had at the beginning of Saturday’s outing. Plus, the Nationals will likely need an innings-eater on the playoff roster. Jackson could be in the running for that job, too.

Saturday, Jackson suffered through his worst outing since joining the Nationals, showing them the dark side that has prevented him from sticking around any team for long. He lasted just 3⅓ innings in which he threw 73 pitches and allowed more than one man to reach for every out he recorded — seven hits, three walks, and five runs.

He never seemed to find a comfortable rhythm against the young and free-swinging Phillies. Catchers Matt Wieters and Jose Lobaton are banged up these days, so Baker gave rookie Raudy Read his first major league start behind the plate. He and Jackson never could solve the Phillies.

“They talked yesterday, but I could tell they were never exactly on the same page because of the amount of time Jackson was taking between pitches,” Baker said. “But Raudy, his first game in the big leagues, he did a pretty good job.”

Given that Lobaton has struggled this season, and considering Pedro Severino has playoff experience, the Nationals could use these weeks to determine exactly which catching option would serve as the best backup in October. Read is not likely to be in the running, though he might be some year soon. He got his third hit in seven big league at-bats to start the seventh inning, which the Nationals began down a run.

Taylor helped them climb that close. His second home run in as many days, the first to go over the wall in that time, brought them to within 5-3 in the fourth. He has now hit 16 homers this season, a career high. Two innings later, Taylor cut the lead to 5-4 with a two-out RBI single. He is 9 for 15 in his last four games and not-so-quietly emerging as a star — just in time for October.

The game remained 5-4 until the ninth, which Taylor led off with a walk. Pinch hitter Wilmer Difo grounded out, but Taylor advanced to second in the process. Read struck out looking, and Baker turned to Robles — who is 20 years old and had never played above Class AA before his recent call-up — to pinch-hit for the pitcher. Robles worked the count to 3-0.

Then he took what looked like ball four but was called strike one. On 3-1, he took the swing the crowd had hoped for — mighty, unapologetic. It missed. On 3-2, he grounded out but was beaten by a half a step on a routine play, conjuring drama from the wholly undramatic, adding intrigue to the inevitable.