STATE COLLEGE, Pa. -- Some expect the 2019 Pirates' starting rotation to serve as a catalyst that will propel the club toward a stronger-than-expected finish. Part of that thinking comes from expected improvement from Trevor Williams and Joe Musgrove, along with Jameson Taillon's continued march toward Cy Young-level performance.
A large part of that faith, too, comes from having a full season of Chris Archer, today's starter in the home opener.
Having paid considerable prospect cost for his services, Neal Huntington has to be clamoring for Archer to serve as intended, as nothing less than a pillar of the rotation alongside Taillon.
For that to happen, Archer's four-seam fastball must be better.
A TWO-PITCH PITCHER
To underscore this importance for Archer's future, we must first go back.
Archer stopped throwing his sinker/two-seam fastball entirely beginning in 2013 with the Rays. In its place came a focused emphasis on the four-seam fastball to pair with his already well-established slider:
Despite flashing a changeup over the years, Archer had essentially become a two-pitch pitcher before he started throwing his sinking fastball again late last season.
Let’s take an aside here: Why did Archer start throwing the sinker again after three years without it? There have certainly been studies in the past in which a sinker has been praised for setting up breaking pitches. This would jibe with Archer's slider being his best pitch. However, as of late -- in the “pitch tunneling” era -- the pitch’s effectiveness as a setup has been diminished.
Perhaps the answer is as simple as Archer needing a third pitch to be less predictable.
No matter the impetus, the re-integration of a sinker will not be as effective as it can be unless Archer's heat gets a bit hotter.
HOW BAD IS IT?
Well, it is pretty bad:
The overall picture that Archer painted with his four-seam fastball last season is a sloppy, confused mess. We see solid average velocity, but not much else. His 18.3 percent swing and miss rate in 2018 -- limited to only four seam fastballs -- ranks him 69th out of 92 starting pitchers with at least 50 whiffs, and is a decrease from 2017's 21.3 percent rate. He cannot point to bad luck as a catalyst for poor fastball performance -- his weighted On Base Average (wOBA) against the pitch is legitimized by an exact same figure in terms of expected wOBA (xwOBA). His expected Fielding Independent Pitching metric was actually nearly a half-run worse than what he ended up with.
This becomes awfully concerning when one notices that Archer's fastball factored into 72 percent of his total pitches in 2018 when viewed through a pitch pairing lens. The data in the graphic above shows the top three pairings that comprised the right-hander's overall pitch selection.
What does it say when a pitch with considerable warts is seen so often?
To me, it says that the pressure on Archer's slider to be great is amplified. Should he catch more of the plate with the slider than he would like, he opens himself to contact. When hitters make contact on that slider, they do so with an average exit velocity of 88.1 mph, putting him at the 10th-highest rate among right-handed starters with at least 50 batted ball sliders.
That pressure becomes amplified when considering just how much harder hitters tagged Archer's heat last season:
Hitters took other liberties with the pitch, including an ugly 14.3 percent HR/FB ratio on the back of a 26.3 percent four-seam fly-ball rate. Both figures put him among the bottom-third of right-handed starters with 150 innings pitched or more.
At the end of they day, only 32 of Archer's 162 total strikeouts in 2018 were completed on a four-seam fastball. This is not necessarily surprising in light of the current state of the now 30-year old hurler's current offerings.
What can be a cause of concern is the predictability of where he likes to finish off his strikeouts when he has a hitter at two-strikes.
First, a look at how his strikeouts ended since coming over to the Pirates at the 2018 deadline:
On the left, you'll see the actual pitches. On the right, you'll see the same pitches but with a slightly easier-to-read representation.
Fastballs up. Sliders down. Got it. Bread and butter. Tried and true. This look jibes with how we have seen his strikeouts finish off for his career:
While one would certainly not expect Archer, or any other starter for that matter, to have an inordinate amount of slider strikeout-finishers above the bottom-third of the strike zone (if in the strike zone at all), what is a bit surprising is just how wide his slider got in two strike counts last season:
To put a number on that graphic, Archer threw 35.7 percent of his sliders on two-strike counts in the top two-thirds of the zone or above. This is a full 20.1 percentage-point increase over the MLB-wide starter rate of 15.6.
WHY ALL THIS MATTERS
I understand that's a lot to digest, but here is why this all matters.
Or, perhaps more importantly, when this matters. At what point ,will Archer feel the sting of a sub-par fastball the most?
The answer lies when he falls behind in the count. First, some context. Last season, right-handed starters threw 11 percent of their total pitches from behind in the count. Archer threw 25 percent of his offerings within the same counts.
League-wide, right handed starters threw the four-seam fastball while behind at a 15.3 percent clip. Archer? 31.8 percent. Again, this should not surprise anyone. To contextualize how far Archer's four-seamer might have to go to be considered sturdy, we need look no further than his rotation mate in Taillon.
Taillon actually threw a comparable amount of fastballs while behind in the count last season, with much better results:
For further context, the 2018-wide MLB rates for righty starters for wOBA and SLG under these parameters came in at .456 and .572, respectively.
Taillon's four-seamer has considerably higher spin than Archer's with similar average velo. Taillon simply gets more out of that additional spin, but is also helped by better sequencing, carrying his now-burgeoning slider and a legitimate curveball. Archer does not have those weapons -- though he did work on his changeup during spring -- to keep hitters off balance.
HOW THE SINKER CAN HELP
To circle back to the re-introduction of Archer's sinker/two seamer, I found a small part of an at-bat in Archer's last 2018 start that might help us see how having that pitch on hand again could help all of his other pitches play up:
By simply being able to come back with a two-seamer rather than a slider or another fastball, Archer was able to mix in a pitch with different movement than the one that opposing hitter Kyle Schwarber just saw. Hitters hunt fastballs early in counts, and Schwarber was likely thinking so here at the second pitch of the at-bat. Going to the two-seamer early kept him off-balance and resulted in an eventual strikeout.
There is room for Archer's fastball to grow. If not in stature, then certainly by first minimizing and then maximizing its usage. Smarter sequencing such as this mini-example shown above could go on to better set up go-to pitches later in at-bats.
You often hear around today's MLB about how pitchers can succeed at a greater clip by throwing their best pitches more often. That's certainly true, but I will add that it might be just as effective to throw your worst pitches less.
In fact, Schwarber only saw four fastballs among the 17 pitches offered to him by Archer on this night.
Schwarber struck out three times, by the way.
I want to take a moment to thank you for investing some time into my first edition of Monday Mound Visit. I'm excited to bring a unique angle on Pirates analysis to the DKPS community. This feature will be fluid from week to week. On some weeks, we might go on a deep dive into nore specific topic as we did today. Others might take a broader view. Still others might be a hybrid of those approaches. I hope you'll enjoy it all.
Please feel free to reach out to me here in the comments, or on Twitter -- @jrollisonpgh -- to offer feedback or suggestions for future topics!
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