NEW YORK -- When he stepped off the mound for the final time in the Mets’ 8-6 loss to the Brewers on Saturday, Noah Syndergaard did so lugging the seventh-worst ERA amongst qualified Major League pitchers. Syndergaard had just allowed five more runs in five innings, raising his season mark to 6.35.

The sample size? Six starts, or somewhere between one-fifth and one-sixth of the season.

Combined with Jacob deGrom's struggles on Friday, Syndergaard’s performance was enough to drop the Mets to .500 for the first time this season.

“There’s no excuses by any of us,” Mets manager Mickey Callaway said. “We’ve just got to be better.”

Callaway struggled to define Syndergaard’s primary issue, repeating only that the pitcher is “not executing” as he should. That much, at least, is plain to see.

By this point in Syndergaard’s career, the Mets had expected him to develop not only into a staff leader, but one of the best pitchers in baseball. An All-Star in 2016 at age 23, Syndergaard lost nearly all of the next season due to a lat strain, then a sizeable chunk of 2018 to a combination of injury and illness. For the Mets, it was concerning, but they could take solace in the upshot: when healthy, Syndergaard was dynamic, with a .627 career winning percentage and a 2.93 ERA entering this season.

That narrative has since changed. Throughout April, Syndergaard has felt healthy and strong, leading MLB starters in average fastball velocity. His 2.93 FIP entering Saturday hinted at a run of poor luck, with a sky-high .346 batting average on balls in play fueling that number.

But Saturday’s loss was about more than mere luck. Early in the game, the Mets’ defense contributed to his troubles, until a replay-reviewed double play in the second inning helped Syndergaard escape a bases-loaded, one-out jam. Faced with an identical problem in the third, he was not so fortunate, serving up an Eric Thames two-run single.

A well-timed, well-placed hit? Fine, perhaps a little lucky. Less so were the solo home runs Ben Gamel and Christian Yelich hit in the fourth inning, raising Syndergaard’s ERA to its highest point this season. When Pete Alonso hit a three-run homer in the seventh inning, it brought the Mets within a run, but no closer.

“When it rains, it pours,” Syndergaard said. “But I’m not pressing the panic button quite just yet. I still have every bit of confidence in my abilities. I’m just not getting the results I want. Something’s not clicking. But I feel like I’m one split-second away from turning this around.”

Suddenly, the Mets cannot be sure what they are getting from Syndergaard even when he’s healthy, spelling trouble for the entire rotation. The Mets built their team around starting pitching, but at the season’s one-month mark, deGrom and Zack Wheeler each own 4.85 ERAs. Syndergaard is at 6.35, and hasn’t been the worst of the bunch. Jason Vargas holds a 7.20 mark. The Mets’ most successful starter, Steven Matz, has a 4.03 ERA, with most of that damage coming during a single inning in Philadelphia.

“We’re just not executing as a staff,” Callaway said. “As a whole staff.”

Combined, the Mets rotation owns a 5.32 ERA, which ranks 24th in the Majors and second-to-last in the National League. The only worse NL team has been the Brewers, who addressed their need by signing free agent Gio Gonzalez late last week. According to Gonzalez and multiple other sources, the Mets were also a finalist for his services. But they would not guarantee him a rotation spot, committing themselves to Vargas for at least a while longer.

That strategy would seem less risky were deGrom and Syndergaard thriving. They’re not. The Mets will find it hard to climb back over .500 until they figure out how to fix it.

“We’ve just got to pitch better,” Callaway said. “Our hitters are keeping us in the games, trying to come back, and we’re not holding them.”