ATLANTA — Manager Terry Collins promised a shake-up, and in the course of an eventful afternoon yesterday, the Mets delivered. Within the span of an hour, Brandon Nimmo was on the way to Atlanta, Michael Conforto was on the way to Las Vegas and Jose Reyes was on the way to Brooklyn.

The Mets swapped a slumping young outfielder for a young outfielder who had surged in Triple-A. Then they reached into their past, signing Reyes and sending him to the minors for a crash course in playing anything but shortstop.

Perhaps the moves eventually will translate into more life for a lineup that has wilted in the heat of the summer. On Saturday night, however, the Mets made 11 innings feel like a root canal sans anesthesia.

With Nimmo watching his first major-league game from the bench, the contours of a 1-0 win over the Braves looked too familiar. Even Reyes at the height of his powers wouldn’t have been able to make a dent in what has become the nightly dysfunction known as the Mets’ offense.

Former Brave Kelly Johnson, obtained by the Mets earlier this month, lined a pinch-hit solo homer in the 11th off former Mets lefthander Dario Alvarez. “It’s nice to come up in a spot where you can do some damage,” Johnson said.

But first the Mets wasted eight shutout innings from Jacob deGrom, endured an embarrassing offensive gaffe in the 10th and needed a double play for closer Jeurys Familia to save it in the 11th.

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The last came after Collins, with one out and a man on second, ordered an intentional walk of notorious Mets-killer Freddie Freeman, a book-shredding move that put the winning run on base.

“It’s smart baseball,” said Familia, who saved his 26th straight to begin the season.

Said Collins: “I’ve just had enough of Freddie.”

Until Johnson’s homer and Familia’s showdown, the Mets appeared to miss their best chance to score in extras.

After Wilmer Flores lined a leadoff single in the 10th and Matt Reynolds pinch ran, scuffling Alejandro De Aza popped up his attempt at a sacrifice bunt.

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A frustrated De Aza spiked his bat into the ground and didn’t bother running. Noticing this, Braves reliever Jim Johnson let the ball drop, then fired to second base to begin a double play.

“When I get told to do something and I don’t do it, it’s frustrating,” De Aza said. “It’s not a good feeling.”

De Aza’s average dropped to .169, though two team sources indicated the Mets are not yet considering releasing him.

The play encapsulated what has been a run of futility for the Mets, who nevertheless gained a game on the NL East-leading Nationals, who are only two games ahead after dropping their seventh in a row.

In Braves righthander Julio Teheran’s most recent start, he had pitched a brilliant one-hit shutout with seven strikeouts against the Mets on June 19. He pitched eight scoreless innings Saturday night, giving up five hits and striking out seven. He has a 23-inning scoreless streak, with the bulk of it his 17 shutout frames against the Mets.

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For the third straight start, the Mets failed to score a single run for deGrom, who sidestepped trouble in stifling heat. In deGrom’s last five starts, the Mets have scored two runs for him.

DeGrom, whose ERA dropped to 2.67, has gone a career-high 10 starts without a win, but he insisted that the lack of run support has been easy to look past. He focused on Johnson’s game-winning hit and what turned out to be a satisfying result.

Said deGrom: “That’s a big win for us.”