The Mets and the Pittsburgh Pirates, one of the best teams in baseball, were tied, 1-1, at Citi Field on Sunday when Pirates pinch-hitter Michael Morse hit a comebacker to the mound in the seventh inning. The Pirates had a runner on first with no outs. It was a routine play, the kind winning teams execute with ease.
Mets reliever Bobby Parnell fielded the ball cleanly, turned to second base and threw, starting what was expected to be a double play. But no one was covering the base.
Ruben Tejada, the shortstop, had been positioned a few steps away from second base, shifting for Morse, a right-handed batter. Tejada sprinted to the bag, lunged for the throw — and missed — and inadvertently blocked the sight of Daniel Murphy, the second baseman, who was backing him up. Murphy ducked, covered his head and stuck out his glove. The ball whizzed into the outfield.
A smattering of boos greeted Parnell’s throwing error. The crowd had just endured a 42-minute rain delay, and the boos grew louder with subsequent miscues in the inning, such as a passed ball off catcher Travis d’Arnaud’s glove that allowed another run.
The Pirates went on to score four runs in the frame, propelling them to an 8-1 win that sealed the sweep of the three-game series. That inning, this game, the entire series, was a reminder that while the Mets are atop the National League East, they are still not on par with the top teams, like the Pirates, who have made the playoffs the last two seasons.
“You’ve got to make the play — end of story,” Manager Terry Collins said. “Should have been a double play. We should have been out of the inning.”
But Collins said it was part of the game and would not assign blame.
“We didn’t make the play; we’re supposed to make the play,” Collins said. “But I’m not going to lump it on one guy’s shoulders — that he was two steps over too far, or the throw was too fast.”
When Collins pulled Parnell from the game, after he had yielded the four runs, two earned, the crowd booed louder than it had for much of the inning. He had been booed Friday, too, when he allowed two runs in the 10th inning of a 3-2 loss. On Sunday, Parnell left the park without speaking with the news media. His E.R.A. ballooned to 5.59 with Sunday’s game, and he took the loss in two of the three games.
“I am a little concerned about Bobby,” Collins said, referring to his mental state.
That one inning had undone what had been a solid start from Matt Harvey, who kept the Mets even with the Pirates despite lacking consistent command.
Harvey threw 103 pitches over six innings, and he let one fastball drift high in the zone that Pedro Alvarez muscled for a solo home run in the second. The Pirates tallied seven hits against Harvey, the most he had allowed in a game in more than a month, including four for extra bases. But Harvey usually responded with a timely strikeout or by inducing a weak ground ball.
The seventh inning might not have been so damaging, had the Mets’ offense performed better. Over the series, the Mets scored six runs in 33 innings, stranded 22 runners and batted 0 for 16 with runners in scoring position. On Sunday, d’Arnaud had two hits, including a solo home run in the second, but the rest of the lineup managed just two hits. Murphy popped out to strand two runners in the first inning and threw his bat in disgust.
The Pirates simply had too much firepower. Five players had at least two hits, and they finished with 15 hits, tying the most the Mets had allowed all season. Aramis Ramirez, one of their new acquisitions, went 4 for 5 and drove in three runs.
Afterward, the Mets dressed in silence and sounded tired and frustrated. They said their day off Monday was well timed. They all tried saying the right things. The series sweep would have felt worse, perhaps, if the Washington Nationals, their division rival, had not lost their sixth straight game Sunday, to the Giants, 5-0.
Murphy refused to say who was to blame for the failed double play.
Tejada said: “I was late to the bag, that’s the only thing.”
Correction: August 16, 2015
An earlier version of a photo caption with this article misstated the point in the game at which Matt Harvey struck out. It was the end of the fourth inning, not the fifth.