Among the early-season strikeout leaders, one finds many of the usual names, pitchers like Chris Sale, Max Scherzer, and Noah Syndergaard. But sandwiched between Syndergaard and Justin Verlander, at seventh overall, is a bit of surprise: J.A. Happ. The veteran lefty has struck out 33.6% of batters faced so far this year.

Because strikeout rate begins to stabilize before almost any other metric, this is a possible first sign that something about Happ is fundamentally different. His swinging-strike rate — another predictive figure — has also jumped, up to 14.1%. He’s never reached double-digits by that measure over the course of a full season.

Over the last four years, Happ’s strikeout rate has hovered between 19.8% and 22.7%. He’s never been an elite strikeout arm, even after his 2015, late-career breakout propelled him to a new level of performance. He entered 2018 having produced a 94 ERA- or better in three straight seasons.

Happ is an outlier. In an era during which more and more pitchers have gone away from their fastballs in favor of swing-and-miss spin, Happ leans about as heavily upon the fastball as any pitcher. He’s thrown the pitch roughly 72.8% of the time this season, most amongst qualified starters. Happ has thrown his best pitches, fastballs, while simultaneously moving away from his slider, changeup, and curveball — all of which rank as negative pitches for his career according to linear weights. Happ’s four- and two-seamer are unique in that they have rare vertical movement separation between them — a point documented by Eno Sarris at the end of 2016.

Throwing your best pitches, more often, makes a lot of sense. Rich Hill is credited with making it en vogue. But Happ arrived there on his own when he jumped his fastball rate by six percentage points in 2016, to a career-high 73.5%. He jumped his two-seamer usage by 15 points.

There’s more to it than simply throwing his best pitch, of course. He also felt he became more efficient in his delivery in 2015 when I spoke with him in Pittsburgh that season. His confidence level spiked. He felt he attacked batters more aggressively.

And he is not only throwing his best pitches more often; he’s using them more effectively, too.

Happ has been one of the pitchers whose conviction in his stuff has been aided by TrackMan Doppler radar. That technology has informed him that he has a high-spin fastball, well above the MLB average for spin (which is around 2,200 rpms). We know that this explains the “rise” effect, and pitches that rise can get swing and miss up in the zone.

Looking over Happ’s four-seamer, one notices that he has increasingly thrown it higher and higher in the zone since 2015.

Happ’s Four-Seamer by Year Season Spin (rpm) Z-Height Whiff % Whiff rank 2015 2,369 2.43 16.93 63rd 2016 2,408 2.54 25.90 17th 2017 2,362 2.65 27.69 6th 2018 2,375 2.78 33.06 4th

It’s subtle, but perceptible, in Happ’s four-seam heat maps from the last four seasons, too…

Happ is going up, and up, and up… and locating more and more inside to right-handed batters.

Here’s Happ elevating a fastball for a strikeout on Tuesday night in the first inning against Boston:

Here’s Happ missing with his fastball over the center of the plate but getting a whiff anyway:

And here’s Happ elevating again against Andrew Benintendi:

Not only has Happ become a strikeout ace, but he’s no longer a fly-ball pitcher in the worst division in baseball to be a fly-ball pitcher.

His two-seamer has either lost some spin as he has advanced into his 30s, or he’s been able to reduce its spin. Its become a ground-ball weapon and reduced some of Happ’s fly-ball tendencies in a hitter’s park. After posting a career-best 46.9% ground-ball rate last year, Happ is again a neutral pitcher this year, having recorded a 46.5% mark so far. Happ’s two-seamer ranks fourth in GB/FB ratio (8.5) early this season after ranking 16th in 2017 (5.84 GB/FB) and 34th in 2015 (4.43). His spin rate has dropped from 2,297 in 2016 to 2,149 rpms this spring and 2,179 rpms last season.

And in updating the aforementioned fastball research by Eno, Happ has some of the greatest vertical movement differential between four-seam and two-seam fastballs (among pitchers who have thrown at least 100 of each pitch type).

While many players are using data to test conventional and improve their skills, the 35-year-old has evolved like few pitchers have in the Statcast era. He’s gone from a back-end, after-thought starer to a front-of-the rotation arm producing 10 WAR since 2015, the 26th-best mark among pitchers.

And, now, maybe Happ’s becoming something even more.