As had been expected since the earliest days of the spring, starting pitching has been the backbone of the Mets' resurgence in 2015. As a group, they are young, they are talented, they are electric.

But as the grind of September wears on and they wade through uncharted territory, they also have shown that they aren't impervious to struggles.

Perhaps it's a reason for concern, a validation for fears that the young arms might wilt beneath the strain of logging innings. Or, it's merely a blip.

In either case, following a 5-0 loss to the Yankees Saturday, manager Terry Collins stated the biggest reason that the Mets must find a way to steady the ship before the postseason:

"If they're going to struggle, they're going to struggle," Collins said, after watching Noah Syndergaard surrender five runs in six innings. "But we're going to go with the guys who brought us to the dance. That's what it's going to be."

Mets starters entered the day with a 4.79 ERA in 16 September games, ranked eighth in the National League. That figure rose after Syndergaard's performance, which mostly hinged on two errant pitches.

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The first was a 99-mph heater to Carlos Beltran, intended to be a touch higher in the zone. Syndergaard missed, but the former Met didn't, belting an 0-2 pitch into the rightfield stands for a three-run homer in the first.

"I left it right in his wheelhouse," Syndergaard said.

In the sixth, the righthander looked to coax a grounder out of Brian McCann by firing a 97-mph two-seamer low and away. But the pitch caught enough plate for McCann to rip a two-run shot.

By then, it mattered little that Syndergaard had retired 12 straight Yankees, the streak broken only because centerfielder Yoenis Cespedes misplayed a deep fly ball into a leadoff triple.

Syndergaard struck out eight and walked none with seven hits, five for extra bases. "I feel like the results don't necessarily dictate how well I threw," said Syndergaard, who pinned the outing on a lack of execution.

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Whatever the reason, Syndergaard's afternoon provided another reminder that the Mets' chances in the playoffs will be firmly tied to a stable of arms that until now have not endured the rigor of a September spent in contention. His 165 innings are the most in a single season in his career, easily eclipsing his 133 innings in the minors last season.

Syndergaard, 23, insisted that he feels physically strong. His mechanics, which can reveal fatigue, remain "on point."

Even Collins acknowledged that aside from two key mistakes, Syndergaard was "outstanding." He said Syndergaard will be a part of the postseason rotation, if the Mets qualify.

Still, the manager offered a reminder of the challenges that young pitchers face near the end of the season.

Said Collins: "You start to run out of gas a little bit, even though you might not feel like it. It's all part of the process."

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But much like speed, stuff doesn't slump for too long, at least in the eyes of Mets captain David Wright.

"Obviously some of these younger guys are getting to some uncharted territory as far as innings," he said. "But the organization has done a good job getting them some extra rest, keeping their pitch counts down. They haven't really gone over 100 pitches too much."

The Mets are banking on those measures paying off. Matt Harvey pitches Sunday night after an 11-day layoff. Jacob deGrom will not pitch on Tuesday, with the Mets hoping that time will help revive his command.

The Mets continue to watch Syndergaard closely, with the intent to keep his outings in the six to seven innings range to save bullets for October.

Said Wright: "When you have that kind of stuff and you can be as dominant as they are, you don't struggle for very long."