Mets relief pitcher Edwin Diaz delivers against Atlanta during the...

Mets relief pitcher Edwin Diaz delivers against Atlanta during the ninth inning in Game 1 of an MLB doubleheader at Citi Field on May 3. Credit: Kathleen Malone-Van Dyke

WASHINGTON — Through his first excellent month of the season, Edwin Diaz has pitched in a way he never has before: throwing his slider for more than half of his pitches — more often than his blazing fastball.

The difference is stark, and it has contributed to his and the team’s success. But the reasons are merely circumstantial, according to those involved, more about the batters he has happened to face and how good that pitch has happened to feel than a philosophical change or a concerted effort to up its usage.

“I’ve been able to command it pretty good. I always try to mix it with my fastball,” said the Mets’ closer, who is 28 years old and in his last season before reaching free agency. “I’ve been able to throw it for a strike. That’s why I more lean now to throw the slider. Because it’s really good.

“I see who is coming to hit. I just follow [catchers Tomas] Nido and [James] McCann and what they call, because they’ve been there all nine innings and they know how the game is going . . . So if they call that pitch, it’s because they know it will be more effective than the other one. I like to follow them.”

Nido laughed that “he’s giving us a lot of credit there,” but he reiterated much what Diaz said. The catchers’ calls for such frequent sliders have been about reading swings, anticipating a hitter’s approach and other “feel” variables.

The result: Diaz has used his slider 52% of the time. His fastball is the other 48%.

Last year, which was in line with his career norms, he was 62% fastball and 38% slider.

 

“He’s got a good one,” manager Buck Showalter said of the slider. “A really good one.”

Hitters have a .111 average and .222 slugging percentage against Diaz’s slider. For his fastball, those numbers are .154 and .385 — still plenty strong, for sure, but not quite as good as the breaking ball.

When Diaz has both pitches working, the other team is in trouble. When he can’t control one or the other, which has happened on plenty of occasions in seasons past, Diaz is the one in danger.

“[Opposing batters] got to box something out with him," Showalter said. "You can’t sit there and say, ‘I’m going to see the ball.’ Good hitters try to box one out,” Showalter said. “Once you show them that you have command of both of those, it presents a really tough front for the other team. Because guys up here can turn around a bullet if you stay with the same look all the time.”

Nido said: “It depends on who is hitting. Some guys we feel will have a better shot at hitting the slider, so we go heater. And sometimes you see a guy sitting dead red and we throw a slider and they look horrible.”

Diaz entered the week with a 1.50 ERA, 0.83 WHIP and six saves in seven chances. He has 21 strikeouts in 12 innings. Opposing hitters have managed one hit every eight at-bats.

Compared to other relievers, Diaz ranks second with a 46.7% strikeout rate (behind only the Cardinals’ Ryan Helsley, who has an absurd 64.5% — basically two out of every three batters).

“I like the fact that when there’s been [failure] — there’s been very few bumps — he gets right back on the horse,” Showalter said. “Next hitter, next outing. Sometimes we think Edwin is 30-something years old. I think you’re seeing a guy evolving into understanding the ups and downs of that job sometimes. He enjoys the ups a lot.”

Is Diaz a 50% slider kind of pitcher moving forward?

“He could be,” Nido said. “It’s not like, 'oh, he has to throw his slider more.' He throws 100, too. It’s so frickin’ hard to hit.”