Is Nathan Eovaldi finally putting it all together?

Along with the ever-exasperating Michael Pineda, Nathan Eovaldi has ranked as one of the more vexing Yankees in recent years. He has long been heralded for his exciting stuff, with his fastball occasionally touching triple digits deep into starts. Yet his poor strikeout numbers have always belied his enticing abilities, and his run prevention has previously left something to be desired. In his first year in pinstripes, Eovaldi posted a 4.20 ERA and middling 7.0 K/9, despite a shiny 3.42 FIP.

This year, however, something seems to have clicked into place. Ever since getting knocked around in Boston for six runs on ten hits on May 1st, Eovaldi has been lights out, running a 2.16 ERA over his past four starts. His season ERA is down to 3.95, and his league-adjusted ERA- is better than league average at 96. Same goes for his league-adjusted FIP- and xFIP- marks, at 87 and 81, respectively. Six years into his career, Eovaldi has not had a season in which all three of said figures were better than league average.

There is still plenty of season left, but Eovaldi's start has been encouraging enough to warrant the question: Is he finally beginning to piece it all together? Through nine starts, it appears as though things are falling into place for Eovaldi to have his long awaited breakout.

A closer look at Eovaldi's performance reveals that there isn't really one significant change that stands out, no smoking gun that completely explains his improvement. Rather, Eovaldi seems to have made several smaller improvements that have thus far added up to a strong season. First, and perhaps most importantly, Eovaldi is finally striking batters out. His 22.5% strikeout rate would easily be a career high, and his 5.9% walk rate is well below his career norms.

His batted profile is promising. Eovaldi has upped his groundball rate all the way to a sterling 54.8%. Just 28.7% of his batted balls have been fly balls, and only 16.6% have been line drives. Furthermore, Eovaldi's plate discipline numbers are also revealing. Here's Eovaldi's figures from 2015 juxtaposed with what he has done so far in 2016 (numbers courtesy of FanGraphs)

Eovaldi has always thrown a good portion of his pitches in the zone. He has thrown even more strikes this year, with over half of his pitches arriving in the strike zone, well above the league average of about 46%. As he has attacked the zone more, hitters have swung more, at an above average rate of 47.6%. However, even with the increased rate of pitches in the zone, opposing batters have made contact at a lower rate. Moreover, the increase in overall swing rate is borne out by an increase in pitches swung at outside the zone, while opposing batters' zone swing rate has actually fallen. It is impossible to know for certain, but such a trend could be attributed to better deceptiveness from Eovaldi.

Is there evidence elsewhere that Eovaldi is evolving to become more deceptive and less hittable? At the very least, his results seem to indicate so. According to Brooks Baseball, in 2015, opposing batters hit .332 with a .453 slugging percentage in at-bats ending with an Eovaldi four-seamer. This season, batters have hit .250 with a .333 slugging. His splitter, which was great last year, has been just as good, yielding only a .187 batting average against.

Batters aren't squaring up Eovaldi the way the have in the past, as the results make clear. What is harder to discern is why. Is it possible Eovaldi is locating better? Looking at how he has located his fastball, that doesn't seem likely:

Eovaldi seems to be locating his fastball in the same general area within the strike zone as he was last year. His splitter, on the other hand, has been located perfectly thus far:

Eovaldi has been letting his splitter dart down and away from hitters excellently, and with good results. Yet that still doesn't explain why hitters have suddenly begun to struggle with his fastball. Perhaps Eovaldi's fastball has simply become a better pitch in his age-26 season. Here's a look at the granular details with regard to Eovaldi's four-seamer in 2015 versus 2016:

Eovaldi has actually bumped his velocity up a bit, despite not yet having had the benefit of pitching through the season's warmer months, when velocities are at their peaks. He has also gotten more run, or horizontal movement, on his four-seamer, while the pitch has had less "rise" this year. Is this enough to conclude the 2016 version of Eovaldi's four-seamer is new and improved? Probably not, but it certainly appears like a step in the right direction.

In all, it is too early to declare that Eovaldi is a brand new pitcher. However, things do seem like they are coming together for him. Striking out more batters, walking fewer, and getting more groundballs is a definite recipe for sucess. Eovaldi discovered his deadly splitter last year, and he has been throwing it even more this year. That alone may be enough to propel Eovaldi to new heights. Going forward, it remains to be seen if he will stay this effective with his fastball the rest of the year. Still, his first nine starts have made one thing clear: Eovaldi has never had a better chance to realize his potential than he does right now.