While the Mets bullpen imploded Friday, this time it wasn’t Edwin Diaz’s fault.

Diaz, temporarily removed from his closer role, finally returned to the mound Friday for the first time since a third straight bad outing last Saturday in Miami.

Manager Carlos Mendoza said he wanted to get Diaz a lower-leverage situation and on Friday, that meant pitching the top of the seventh against the Giants with a three-run lead in an eventual 8-7 loss.

After jogging to the mound with a toned-down version of his typical “Narco” entrance music, Diaz responded by tossing a scoreless inning.

“Today was really good,’’ Diaz said. “I’ve got to keep working. I think it was my best outing this season.”

With better command of his fastball and slider, he allowed a single, struck out two and walked off the field to chants of “Edwin Diaz” from the Citi Field crowd.

Afterwards, he said he was ready to resume closing if asked.

“I would feel OK,’’ Diaz said. “If they give me the ball [Saturday] in the ninth, I will be ready.”

Mendoza praised Diaz’s performance, especially the “conviction” with which he threw his pitches and didn’t rule out using Diaz in the ninth inning, but made no guarantees.

Prior to the game, though, he made it clear that Diaz would be back there at some point.

“For us to get where we want to get to, we need Edwin Diaz to be at his best and I’m pretty confident he will get there,’’ Mendoza said. “This is too good a pitcher for this to continue.”

Diaz acknowledged that his confidence had been an issue during his recent poor stretch and Mendoza said that’s what’s impacted his performance.

And that’s what Diaz has been trying to improve on as he looks to return to form after missing all of last season with a torn patellar tendon in his right knee.

“We don’t want to go too far out without giving him an opportunity to close a game out,” Mendoza said. “That’s who he is. He’s our closer. He’s just going through it right now, especially from the mental side of things.”

Brandon Nimmo was drilled in the head by a 91-mph fastball from San Francisco’s Kyle Harrison in the bottom of the third of Friday night’s game at Citi Field and somehow remained in the game despite clearly being staggered by the pitch.

The ball hit Nimmo in the ear flap he has attached to his helmet, which certainly prevented more damage.

“I added that last year and it saved me,’’ Nimmo said. “I just know I was surprised. I was just trying to regain everything when I got hit. “

He was kept on his feet by J.D. Martinez, who walked over from the on deck circle as Nimmo stumbled in his direction, shaking off the effects of the plunking.

After being checked out by the Mets’ training staff, Nimmo remained in the game and stole second base.

Francisco Alvarez is set to take batting practice Saturday for the first time since undergoing surgery to repair a torn ligament in his left thumb in April.

The catcher is still wearing a splint and is unsure when he’ll be able to get back into the lineup, although Mendoza has said the Mets hope to get Alvarez back sometime late next month.

“I feel a little better,’’ Alvarez said before Friday’s game.

If all goes well Saturday, Alvarez said he would start hitting off a machine.

Alvarez added he would be back “when everything feels 100 percent.”

Drew Smith, still rehabbing from right shoulder inflammation that’s kept him on the IL since April, is set to make a rehab appearance Sunday for high-A Brooklyn, according to Mendoza.

Smith had been shut down with a recurrence of soreness in the area, but he is scheduled to throw an inning Sunday.