Casey Fien and Spin Rates

marc w · December 6, 2016 at 5:30 pm · Filed Under Mariners 

Not that long ago, I had a post about some early contenders for the bullpen pile after the M’s acquired Dean Kiekhefer in a waiver claim. With his low 3/4 delivery and the resultant horizontal movement, he looked a bit like fellow new-Mariner, Ryan Weber. Two things are clear at this point, some 13-14 months into the Jerry Dipoto tenure: first, the man cannot stop acquiring relievers, and second, when he does, he seems to like to acquire two or three guys with the same approach/skills.

I thought back to that “buy in bulk” strategy when looking into new Mariner Casey Fien. John Trupin has a handy overview of Fien over at Lookout Landing. The short version is that he was once a perfectly, er, fine member of the Twins bullpen, who was absolutely destroyed by the home run ball last year. His career walk rate is under 5% too, so at first glance, this looked a bit like acquiring another Evan Scribner. Solid K-BB%, horrific HR/9 buy-low guys who can appear to improve a ton thanks to some regression in their HR/FB rates. Scribner gave up an astonishing 14 HRs in 60 IP for Oakland in 2015, which is why he was available for a low-level prospect despite posting one of the best K-BB% marks in all of baseball. Well, Fien gave up 13 HRs last year in just 39 1/3 IP, good for a vertiginous HR/9 of 2.97. That’ll get you waived, and indeed, Minnesota waived him last year. He caught on with the Dodgers, but didn’t fare any better, so he’ll cost the M’s $1.1 million if he sticks on the MLB roster.

The more you look at how he pitches, though, the less like Scribner he looks. Scribner has a fairly high-spin fastball, at 2,286 RPMs and a 91mph velocity. Fien actually blows Scribner out of the water in this measure, with a high-spin, 2,501 RPM fastball at 93.9mph. To borrow a concept from Kyle Boddy, who likes to use the ratio of RPM to MPH, Fien still gets more spin per MPH than Scribner, and more still than the MLB league average ratio for four-seam fastballs.* Looking at each pitcher’s curve, the picture’s reversed. Scribner has elite curveball spin (well over 2,800 RPM, compared to a league avrerage of 2,471), which I’m sure was something that attracted the attention of the M’s analytical staff. Fien’s comes in at 2,620, so higher than league average, but far short of Scribner’s. But look at pitch movement, and they look completely different: Evan Scribner’s fastball has a lot of effective spin, meaning the spin is producing movement (in this case, rise). Fien’s four-seam rises a tiny bit more than average, but it’s nothing to write home about. Fien’s second pitch, a pitch he goes to about *40% of the time* is his cutter, which again has remarkably high spin rates (2,500+ RPMs) and not much in the way of actual movement. Does this sound familiar?

This high-spin, meh-movement repertoire was something I spent far too long discussing in the context of Rob Whalen, another new Mariner. Fien’s cutter looks a bit like Whalen’s odd fastball. Both come in around 90mph, have ~0 horizontal movement, and less-than-normal-fastball amounts of vertical rise. As cutters produce, *on average*, worse contact, a team might want to look at high-spin pitchers who, for whatever reason, don’t get much transverse (movement-causing) spin on the ball. That’s the theory, anyway. On the field, Fien’s cutter got obliterated last year, with batters slugging .649 on it. Even looking at his career as a whole, they’re slugging .452, which is pretty high for a reliever who’s spent his career in the low-scoring 2010’s. That said, it may help disguise his flat four-seamer, which has been pretty effective for him, 2016 aside. If the M’s think he was tipping his pitches or have some other tweak in mind, he’d be a perfectly serviceable middle-relief guy, though it’s worth noting that the M’s bullpen’s already pretty full. In any event, while Fien is definitely not a clone of Rob Whalen, there are some surface similarities that make me wonder if they’re traits that the M’s are actively searching for.

I’d love to know more about how teams value gyro spin, and why it might be useful. In the public analytical space, we tend to focus on movement, and for some very good reasons: high-spin, high-movement curves really do seem to be “better.” But I’m not at all convinced that gyro spin is bad in a *slider.* A high-spin, low movement fastball might also provide some sort of advantage, either by producing weaker contact or by confusing hitters whose swing paths essentially build in the horizontal movement that nearly all fastballs have. Spin efficiency, the ratio of transverse to total spin, is useful in some contexts, but less so in others. Why is that, and how might a pitcher’s arsenal – or pitch sequencing – take advantage of it?

* Boddy calls this ratio “Bauer Units.” The league average for four-seamers was 24.3 last year. Scribner’s fastball ranked at 25.3, while Fien was up at 26.6. Using his league indexed BU+ measure, Fien comes in at 109.


4 Responses to “Casey Fien and Spin Rates”

  1. bookbook on December 7th, 2016 2:09 pm

    1) This is very interesting. It seemingly gives a way to compare pitches of different pitchers, and at least speculatively, see the potential where results have not quite been before.

    2) These sabr breakthroughs really come in waves, don’t they? I remember when all of the interesting articles were about babip. Then, a couple of years later, it’s all pitch framing. It looks like the shiny new toy of 2016’s offseason may be spin rate. Like the other two before, we’ll probably discover spin rate is important and meaningful, but not as comprehensive as we first thought.

    I wonder, are pitchers’ spin rates consistent through the year? Or does the rate fluctuate when they tire later in the game? Maybe warmer weather or end-of-year fatigue plays a role? Is the spin rate different below the equator? There’s definitely much to explore.

  2. Longgeorge1 on December 7th, 2016 8:30 pm

    In “Moneyball” Billy Beane was asked about how he managed to find so many low cost arms to fill out his bullpen. Hes stated that he wasn’t that good, he went through about 50 guys. When he found someone effective he kept him. When that player lost the magic, it was next man up.
    I think Dipoto shops at Costco.

  3. Alec on December 9th, 2016 1:50 pm

    The bullpen and corner AAAA players is exactly where shopping in bulk makes sense. Both have such a large supply that they come cheap, meaning they’re easy to cycle through if management is ok with the strategy. Also, both have tendencies to suddenly fall off cliffs or generate interest from FOs looking for splashy moves if they hit.

  4. stevemotivateir on December 26th, 2016 5:33 pm

    Crap, I’m catching this way too late, but still felt compelled to comment, even if only to the harmony of crickets.

    I had taken a hard look at the spin rates via Baseball Savant a month or so ago, and as Marc pointed out, or at least hinted at, Kiekhefer is in that conversation as well.

    So is Blevins, so if Dipoto is focusing on this particular skill, maybe we can get an idea who might be on the radar?

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