PITTSBURGH – That Zack Greinke is reinventing himself, that he remains effective even as his velocity leaves him, that he has bounced back while pitching in front of a better defensive cast this season — none of it should represent one of the greater shocks of the 2017 season. After all, this is an elite-level athlete with excellent command, one who owns a five-pitch mix and a feel for the craft. He is also a diligent student of the game.

Before I caught up with Greinke this week in Pittsburgh, he was seated at a card table before a laptop, a sort of make-shift video and data center hastily constructed each series in the center of the opposing clubhouse in PNC Park, a common setup for the road traveling party. Greinke was several days away from his Thursday start in Miami, but he was one of the players seemingly most interested in studying upcoming opponents. Greinke embraces data and — shameless plug alert — is a reader of FanGraphs.

Greinke has stuff, smarts, guile, and experience. Even with declining velocity, he was a good bet to age well. And what’s interesting is that, as his four-seam fastball sits at a career-low average velocity (90.4 mph), he’s not declining at all. Rather, he’s posting some of the best numbers of his career. Greinke owns the best strikeout percentage (29.6%) and strikeout-walk rate differential (24.7 points) of his career, which is saying something for a Cy Young winner and one of the best pitchers of the 21st century.

His resurgence is a significant reason why the Diamondbacks appear to be significant contenders in a weak NL.

Greinke is back, as Dave Cameron wrote in early May, largely fueled by his slider. Wrote Cameron:

Last year, opposing hitters made contact 91% of the time they swung at a Greinke slider in the strike zone; this year, that’s down to 68%. Three out of four times, Greinke puts his slider out of the zone, but this year, the pitch is also getting whiffs in the zone, allowing him to get extra strikes and pitch ahead in the count more regularly. And when you’re pitching ahead in the count, then hitters are going to expand the zone, and chase more of the pitches out of the zone that he’s throwing.

The pitch is producing the most out-of-zone swings in baseball this season, and it trails only Clayton Kershaw’s slider in whiffs per swing at 51.7%. The pitch is eighth among starting pitchers’ sliders in horizontal movement (4.03 inches) and 13th in vertical movement (2.13).

Last season, Greinke’s slider ranked 30th among qualified starters in whiffs per swing (38.3%), 21st in horizontal break (3.92 inches), and 64th in vertical movement (1.38 inches). Even in Greinke’s second-place Cy Young finish in 2015, his slider wasn’t as good as it is this season, generating a 38.7% whiff-per-swing rate, ranking 22nd. This is the best Greinke’s slider has ever been, and the best since his his breakout 2009 season, when he finished second in whiff-per-swing (45.3%) among qualified starters.

The slider is fueling his swinging strike rate, resting at a career-best 14.3%, a rate which also leads leads MLB starting pitchers. All this is occurring in a season when his fastball is 2.5 mph below the MLB average for the pitch.

Greinke’s slider is a filthy pitch, just ask Keon Broxton:

But what I was curious to ask Greinke is if he considered himself part of the movement to replace fastballs with spin pitches as primary offerings, or have spin become nearer to primary offerings. Was he inching closer to the Rich Hill and Lance McCullers school of pitching. Greinke is aware of the movement.

Not only has Greinke’s slider been great, he’s also throwing it at a career-high rate (26.7%) and has increased its usage in each of the last five seasons. Last year, 51.3% of his pitches were fastballs. For his career, 55.5% of his pitches have been four- or two-seam fastballs. This season, his four-seam usage is down to a career-low 32.4% and his total fastball usage is a career-low (47.3%). For the first time in his career, the majority of his pitches are not fastballs. Greinke’s fastball is no longer a majority leader among his pitch constituency, rather it’s fallen to status as merely a plurality leader.

Greinke acknowledges that he’s made changes to pitch mix, but he hasn’t considered becoming a primarily non-fastball pitcher, even if his pitch mix is advancing in that direction.

Greinke said he is aware of what Hill is doing with a 50-50 fastball-curveball mix in L.A., though he considers the different arm angles Hill uses to create the illusion of throwing a wider variety of pitches. He insists not trying to become Hill or McCullers.

“My slider [usage] has been up a little, changeup has gone down a little, curveball is about the same,” Greinke said. “I like to throw as many fastballs as possible, but you have to be smart, too.”

And perhaps “being smart” is being cognizant of a velocity dip.

Still, whether he’s consciously or subconsciously inching toward the Rich Hill Phylum of pitchers, he is.

Arizona pitching coach Mike Butcher said there was a never a conversation about Greinke relying on his slider more but that he credits the pitch, at least in part, to his bounce-back year.

“The biggest thing that stands out is the slider has been sharper this year,” Butcher said. “I just think how he’s working over the ball with his finger. There’s a little more tilt than I’ve seen, not two-to-seven [o’ clock], or two-to-eight, but one-to-seven, or one-to-eight. It’s shorter and sharper.”

And perhaps his slider is the best it has ever been because Greinke is throwing it more often than he ever has, the idea that “feel” for pitching is tied to uninterrupted building of muscle memory.

While Greinke’s velocity has rebounded some since the spring, Butcher said he was never concerned about the drop.

“Go back to spring training. Everyone was knocking him because his velocity is down,” Butcher said. “I could not care less as long as he felt good and was repeating everything. His front side is higher than in spring training, for sure. I think that allows him to have more leverage. [It’s] not as high as it was in L.A., but it’s still really good. He’s creating good balance in his back side. His timing is on point all of the time.”

While first-year Diamondbacks catcher Jeff Mathis has been praised for his framing, which had undoubtedly helped Greinke, Butcher went out of his way, unprompted, to praise his pitch calling. And it is Mathis who also has played a role in Greinke’s increased slider usage.

“It’s been really good lately,” Mathis said of the slider.

Mathis said part of the increased slide usage has been by design, but it’s also largely based upon what he is seeing in-game.

“I also think it’s reading hitters’ swings through the course of the game,” Mathis said. “They may not be seeing the ball well. [The slider] may be really, really working that day. It’s something we’ve gone to do quite a bit.”

Greinke is in a better place. He is a great pitcher more often employing a great pitch, a pitch who has never been more effective. It seems to be a winning formula.