Jose Valverde has a reputation as the kind of closer who is an angst-provoking tightrope walker. But lately he has lost his footing and fallen into what Mets manager Terry Collins termed the "nitro zone," meaning he's throwing pitches where they tend to explode off opposing bats.

Valverde surrendered a three-run homer in the top of the ninth inning to Justin Upton that proved the difference in Atlanta's 7-5 victory Saturday night in front of a Citi Field crowd of 31,476. It was the fourth home run Valverde has given up in his past three appearances and the second time in his career he has allowed homers in three straight games.

It also might have cost him the job as the Mets' closer even though there is no obvious alternative with Bobby Parnell lost for the season after Tommy John surgery. When Collins was asked if he'll change closers, he pulled no punches. "We need to talk about it for sure," he said.

Valverde was not available to answer questions after the game, but four home runs allowed in just over eight innings is intolerable for a team like the Mets with a slender margin for error.

They trailed 4-1 when Braves starter Ervin Santana (2-0) left after seven innings but got to reliever David Carpenter for two runs on four hits in the eighth.

Daniel Murphy and David Wright led off the inning with singles and scored on singles by Chris Young and Travis d'Arnaud, respectively. In between Young and d'Arnaud, Lucas Duda lofted a one-out shot that seemed destined for the rightfield stands before it died on the warning track.

"I thought it was a home run," Collins said. "If nothing else tells you how hard it is to hit a home run [here], that ball does."

Subscribe to Newsday’s sports newsletter Receive stories, photos and videos about your favorite New York teams plus national sports news and events. By clicking Sign up, you agree to our privacy policy.

The rally ended with a groundout by Ruben Tejada before Collins brought in Valverde to pitch the ninth in a one-run game. Pinch hitter Jordan Schafer reached base on Valverde's error, but he struck out Jason Heyward and got B.J. Upton to foul out. Schafer had stolen second, so Freddie Freeman was intentionally walked. But Justin Upton drove a 2-and-2 pitch to right-centerfield that was gone when it left the bat.

Recalling the homers Valverde allowed in his previous two outings, both Mets wins, Collins said, "The other night he threw two balls in the nitro zone. He must have done the same thing tonight."

"He's leaving the ball up," d'Arnaud said. "That's it."

The Braves took a 7-3 lead to the bottom of the ninth, but the Mets got to Atlanta closer Craig Kimbrel for a run-scoring double by Wright and Young's two-out RBI single to make it a 7-5 game. Kimbrel walked Duda to load the bases and was relieved by Jordan Walden, who got d'Arnaud to ground into the final out.

The two teams might have gone to extra innings if not for a third-inning play that was called incorrectly by the umpires but ultimately was not reviewable under the new replay rules.

Mets starter Bartolo Colon (1-3) had runners at first and second with two outs when Freeman chopped a ball in front of the plate. Colon fielded it but threw wildly to first base, allowing both runners to score. Replays showed the ball actually was fouled off Freeman's lead foot, but the rule states replay may be used to determine fair or foul calls "only with respect to ball that first land at or beyond the set positions of the first or third base Umpire."

It turned out to be the difference at the end.

"I thought it was a foul ball," Colon said. "That's why I didn't run quickly to grab it. I was waiting for the umps to say it was foul."

Asked if that type of play should be reviewable, Colon said, "We're reviewing other plays, why not that one?"