SSNS: C. Anderson, Stroman, L. Castillo

Last week, I reintroduced my Small Sample Normalization Services (SSNS), analyzing strong starts by Dylan Bundy, Jose Berrios, and Patrick Corbin in the context of other small samples within their respective careers or recent histories. This time, I discuss three more odd starts among starting pitchers and their implications.

Chase Anderson, MIL SP

Anderson’s 6-game rolling swinging strike rate (Swstr%) is at its lowest point (7.1%) since before he was good (aka 2016). You wouldn’t know it by his results thus far — a 2.86 ERA and 1.01 WHIP through 34.2 innings — but the negative wins above replacement (-0.1 WAR) and 4.70 ERA speak volumes about his good fortune (.196 batting average on balls in play (BABIP), 96% strand rate (LOB%)).

His change-up, his best pitch last year, has seemingly lost its bite, managing an anemic 10% whiff rate compared to last year’s 16%. The pitch, however, also induced an equally weak whiff rate last April before picking up steam and carrying its momentum through September. Maybe, for whatever reason, this specific pitch takes a few starts to heat up. I’ll cut Anderson some slack and assume this is somehow a reliable trend.

Regardless of the change-piece, it’s Anderson’s four-seamer that should bring us concern. Something magical happened in September 2016, during which Anderson’s fastball notched a 13.6% whiff rate (and actually set the table for 2017’s breakout): he changed his release point. As I mentioned last week, I’m still not sure if a change in horizontal release point means Anderson simply moved over on the rubber or he actually changed his arm slot, especially when there’s no discernible change to the vertical release point. Regardless, it’s an adjustment that produced strong results — an adjustment he carried through 2017 and then seemingly abandoned in 2018. Concurrently, the pitch’s whiff rate slipped into the single digits.

As it stands, Anderson is a ticking time bomb. But, also as it stands, Anderson may be a small adjustment away from recapturing 2017’s glory. He’s an obvious sell-high candidate, but keep an eye on his release points moving forward.

Marcus Stroman, TOR SP

It has a rather unflattering start for the Blue Jays ace, whose 5-game rolling average chase rate (O-Swing%) reached its lowest point since mid-2014. But that’s not necessarily a function of declining “stuff” — his overall swing rate (Swing%) has bottomed out in dramatic fashion.

For this, I don’t have an answer. Stroman’s release points and pitch locations look normal enough, as do his zone profiles. So why are hitters leaving their bats on their shoulders? Fortunately, Stroman’s whiff rate is normal, as is his strikeout rate. But the lack of swings have made him especially vulnerable to free passes. Until it gets sorted out, or at least until some kind of explanation surfaces, he’s kind of a risky starter in shallow formats.

All that said, his 46% strand rate is improbably bad. Stroman has never excelled in this regard, but also, no one in the last decade has stranded so few runners in the first month of the season. It’s unsustainably bad, and it’ll regress. On this basis, Stroman is good bounce-back candidate, and his 4.18 SIERA, fueled by a 65% ground ball rate (GB%), suggests he’s plenty valuable even with a concerning walk rate. Buy low, obviously, but don’t hold your breath for a 2017 repeat (it was a little lucky anyway).

Luis Castillo, CIN SP

It’s taking every ounce of my strength not to write about Masahiro Tanaka or Luke Weaver again… so, I’ll turn my focus to Castillo. Let’s first deal with the obvious: the 58.1% strand rate, like Stroman’s is remarkably bad and, as history shows us, will not continue to stay this low. Moreover, it’s too early to expect that, after exhibiting above-average contact manage through his first 15 starts, he’s suddenly below-average in this regard. Through 118 innings, his career BABIP stands at .271; until further notice, he shouldn’t be considered worse than league-average (.300 BABIP). That 7.85 ERA ain’t sticking around.

What’s weird with Castillo is the disparity between his strikeout and whiff rates. His in-season rolling 6-game swinging strike rate has never been better, yet his rolling strikeout rate has tanked. Last time the aforementioned rolling strikeout rate was this low — 19% from July 15 to August 10, 2017 — Castillo was inducing whiffs 10.8% of the time, which was also nearly a career-low at the time. The two rates have tracked each other pretty well to this point. My mental rule of thumb for converting SwStr% to K%: double it. Castillo’s 13.5% swinging strike rate warrants a strikeout rate closer to 27%, give or take a couple of percentage points but clearly much higher than his current 18% K-rate. Castillo’s 4.62 SIERA paints the picture of a wildly mediocre pitcher, but it, of equal wildness, underestimates his strikeout potential.

Two things might be true: (1) Castillo probably overperformed his strikeout rate by a couple of ticks last year; (2) Castillo may not sustain the lofty level on his current swinging strike rate. Neither detracts from the high likelihood of his strikeout rate climbing several ticks over the course of the season. (The whiff rates on his individual pitches are all over the place, so I’m not yet relying too heavily on them. It’d be nice to see his slider rebound, though.) His current metrics with a 25% strikeout rate produce a mid-3.00s SIERA. If you drafted Castillo, you have to hold him. All pitches face adversity — even sophomores who seemed immune to it as rookies.