ATLANTA — As Mets manager Mickey Callaway attempts to figure out roles for his relievers, this much seems clear: Edwin Diaz will only pitch when there’s a cushion or the team is losing.

With Seth Lugo elevated to pitch in the Mets’ highest-leverage situations (including closing), Callaway was asked Tuesday about the possibility of using the struggling Diaz in a setup role.

“If things had been going a little bit different for [Diaz] it would make more sense,” Callaway said before the Mets lost 5-3 to the Braves at SunTrust Park. “But right now I think you are going to see him toward the back and we’ll go from there.”

Diaz is 1-6 with a 5.60 ERA for the season. Since April 29 he has pitched to a 7.08 ERA.

“In a high-leverage situation, the way things are going for him it’s hard to put him in in that spot,” Callaway said.

Following Monday’s day off, the Mets had Lugo available from the bullpen to close, with Justin Wilson as the primary setup option but didn’t use Lugo, Wilson or Diaz.

Jacob deGrom took the blame for Pete Alonso’s error Sunday that gave the Nationals three runs in the first inning of the game they won 7-4. Alonso fielded a grounder and threw to deGrom covering first base, but the ball hit deGrom’s glove and rolled into foul territory, as the bases cleared. DeGrom hesitated as he approached the bag, but he said that wasn’t a factor.

“I have watched that a few times because it bothered me and I should have caught that,” said deGrom, who was unavailable to speak with the media after Sunday’s game because he had to catch a flight home. “I don’t think that hesitation prevented me from catching it because if you don’t slow down, what are you going to do run past the bag? You have to slow down at some point. Just the way I cover first, that is how I do it and I feel that helps you get a throw that could be a little off and now you slowed down.”

The Mets recalled Drew Gagnon, who pitched a scoreless eighth inning Tuesday, from Triple-A Syracuse and optioned Chris Mazza. According to Callaway, the move was made because of concern Mazza, who last pitched July 18, had become rusty.

Jeff McNeil had a hit subtracted from his season total, as MLB ruled an at-bat on which he was credited with a single Aug. 3 in Pittsburgh was actually an error by Pirates first baseman Josh Bell. With the scoring change, all three runs in the inning were unearned.