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

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

Perhaps, the moves eventually translate into more life for a lineup that has wilted in the heat of the summer. But on Saturday night, 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 couldn’t make a dent in what has become the nightly dysfunction known as the Mets offense.

Kelly Johnson, traded from the Braves earlier this season, lined a pinch hit solo homer in the 11th inning off lefthander Dario Alvarez, a former Met.

“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.

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 Braves’ winning run on base.

“It’s smart baseball,” said Familia, who got a double play and 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, Matt Reynolds pinch ran, but scuffling veteran Alejandro De Aza popped up his attempt at a sacrifice bunt.

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

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

“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.”

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

For the third straight start, the Mets failed to score a single run for deGrom, who sidestepped trouble while working through stifling heat.

Meanwhile, Julio Teheran’s last start came against the Mets on June 19, a brilliant one-hit shutout in which the Braves righthander struck out seven. He didn’t look that good on Saturday, but he wasn’t that far off, either.

He finished with eight scoreless frames, giving up five hits with seven strikeouts. He has a 23-inning scoreless streak, the bulk his 17 shutout frames against the Mets.

The Mets collected four hits through the first three innings, the last coming on a Yoenis Cespedes single that was wasted because he attempted to stretch it into a double.

From there, Teheran clicked into cruise, retiring the next 15 batters until Curtis Granderson’s two-out single in the eighth.

Over deGrom’s last five starts, the Mets have scored just two runs for him. They have none in each of his last three outings.

Not since June 7 had deGrom looked at the scoreboard during one of his outings and seen anything but a zero next to the Mets’ total. Even then, the figure he saw was modest: one.

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 instead on Johnson’s game winning hit and what turned out to be a satisfying result.

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