Edwin Diaz of the Mets throws a pitch in the...

Edwin Diaz of the Mets throws a pitch in the ninth inning against the Braves at SunTrust Park on Thursday in Atlanta, Ga. Credit: Getty Images/Mike Zarrilli

ATLANTA — Edwin Diaz’s numbers in the opening half-month of the season look perfectly fine: 1.59 ERA, five saves in five chances, 10 strikeouts to one walk in 5 2/3 innings heading into the Mets’ game Friday night against the Braves.

But it hasn’t quite been the same dominant Diaz the Mets acquired from Seattle in December.

“He’s not at his best yet,” pitching coach Dave Eiland said. “And he’s still doing very good.”

All of the small-sample-size caveats apply, given the early stage of the season, but opposing batters have hit Diaz very hard: 93.6 mph on average, according to Baseball Savant. That is considerably higher than the MLB average (87.4 mph) and Diaz’s career average (87.6). It’s even more extreme on pitches up in the zone.

Manager Mickey Callaway, far from sounding any alarms about his closer, attributed that to Diaz’s recent tendency to leave pitches over the middle of the plate.

“It’s just throwing the ball over the heart of the plate doesn’t seem to work most of the time against major-league hitters,” Callaway said. “All those balls that are getting hit hard are right down the heart of the plate. The strikeout numbers are there [42 percent of Diaz’s batters], so I’m not concerned about that. He just needs to keep the ball out of the center of the plate a little bit more.”

Also factoring in, according to Eiland: Diaz is putting extra pressure on himself, having joined the team alongside Robinson Cano in the Mets’ marquee offseason transaction.

"It’s early, it’s a new league,” Eiland said. “People need to take into account, I don’t know if he was the centerpiece of that trade, but he was a huge part of that trade. And now he’s coming in here and he’s trying to be really good. I have no concerns about him.”

Despite the team’s overall success, the Mets’ bullpen overall has been a weakness.  Their relievers had combined for a 6.25 ERA — a bottom-five mark in baseball — heading into play Friday.

Callaway cited their .379 batting average on balls in play, the highest of any bullpen and significantly higher than the norm of about .300, as evidence that the relievers as a unit have gotten unlucky.

“The pitching is going to turn around just because of the law of averages,” Callaway said.

Nimmo gets dropped and produces

For the first time this season, Brandon Nimmo batted somewhere other than leadoff, dropped to the No. 8 spot. And he went 3-for-4 with a homer and a double in that spot on Friday.

Nimmo, who had nearly four times as many strikeouts as hits (23 to 6), went 0-for-4 with two strikeouts Thursday, helping to push Callaway to that decision.

“Hopefully he’ll either get pitches to hit or he’ll get nothing at all and walk like he’s so good at doing,” Callaway said.

Nimmo understood.

“It’s not a problem at all,” he said. “Obviously, they know I’m very capable, so they’re just trying to switch things up. Sometimes a different look can help things.”

Extra bases

Pete Alonso sat Friday for the second time in 13 games. “Right now, Alonso would never have a day off if we went on just him being hot,” Callaway said. Alonso’s 12 extra-base hits in his first 12 career games were the most since 1900. … Justin Wilson was sick most of the week and had not pitched since Saturday. He tossed a perfect seventh inning Friday … Jed Lowrie (sprained left knee capsule) still is with the Mets and progressing slowly in his rehab, but has advanced to practicing running the bases, albeit not at full speed.

Newsday LogoYour Island. Your Community. Your News.Digital AccessOnly 25¢for 5 months