Risers and Fallers: Volume 11
I’m excited to be back for another week of Risers & Fallers! Each week, I’ll break down a handful of players using advanced metrics, insights from my scouting background, and my DFS projection system THE BAT (available in the RotoGrinders Marketplace), which consistently beat Vegas lines last year.
I’ll examine guys whose stock is going up, guys whose stock is going down, guys who are perpetually underpriced or overpriced, guys who are worth paying a premium for, or guys who are just interesting and warrant some analysis on. If you guys have any suggestions for who you’d like to see in future articles, feel free to let me know.
Rising… and Overrated
Swinging Strike Rate… while Aaron Nola is rising and very much not overrated
It’s time again for me to attack (a.k.a. make rational, well-reasoned, well-supported mathematical arguments against) a widely loved “advanced stat” and face less well-reasoned ridicule from the DFS crowd that has a tenuous grasp on math and will only choose to make it a few sentences into this before spouting off. But a man’s gotta do what a man’s gotta do: swinging strike rate is overrated.
That’s not to say it’s completely useless or that it can’t be used as a valuable piece of information, but it does tend to get highly glorified in this modern age where people find the shiny new toy and cling to it for dear life come hell or high water. (Maybe that’s mixing metaphors a bit, but let’s pretend the toy is a pool floatie glistening in the sun. All good now.)
The primary purpose of swinging strikes is to predict strikeouts, and it makes sense why that would be the case: strikes lead to strikeouts, and swinging strikes are a type of strike, are a good indicator of “stuff,” are very stable, and are a good predictor of future strikes. Part of my issue with swinging strikes, though, is that swinging strikes are only one kind of strike. While swinging strikes are more “stable” than called strikes are, called strikes are still strikes and they are generated more often by certain types of pitches and “stuff”.
Let’s use Aaron Nola as an example. Nola has been excellent this year, posting a strikeout rate 18% better than league average while posting a swinging strike rate 3% worse than average. Last year his swinging strike rate was 5% worse than average. While the staunchest swinging strike devotees may say this bodes poorly for Nola, that regression may be coming for his strikeout rate, they would be incorrect.
Nola’s stuff isn’t your typical swing-and-miss stuff, but it is able to generate a healthy amount of strikeouts regardless. To start with, Nola throws his four-seamer and his sinker a combined 55% of the time. The sinker especially is a quality pitch, but he only throws each 91 mph; they’re not blowing hitters away. Both project to be above average for called strikes and well below-average for swinging strikes (and have generated corresponding results). Sinkers in particular are the worst swing-and-miss pitch in baseball, and Nola throws his over 40% of the time. That’s because the purpose of sinkers isn’t to miss bats; they’re for generating grounders and for pounding the zone to get ahead in the count.
As everyone knows, Nola’s best pitch is his curveball—one of the best in baseball. But while it’s an elite curveball, it’s not your typical fool-the-hitter-into-swinging-over-it-and-generate-an-absurd-amount-of-whiffs kind of elite curveball—either from a scouting perspective or in terms of results. It can certainly generate swinging strikes and does so at an above average rate, but it strikes a much stronger balance between swinging strikes and called strikes than the elite curveballs of pitchers like Alex Wood and Lance McCullers. As I’ve discussed previously, these guys have elite curveballs because they throw them hard, they throw them low, and they hide (or tunnel) them exceptionally well inside their fastballs—leading to far more swinging strikes than called strikes as hitters don’t realize they are curveballs until it’s too late. Nola’s is different. While McCullers and Wood sit in the low-80s with their hooks, Nola’s is just 76 mph. It’s slower, it has more vertical movement, and it has a larger hump and tunnel. These types of curves generate a far higher percentage of called strikes and, as a result, lead to lower swinging strike rates.
All told, Nola hasn’t been “lucky” with strikeouts because his swinging strike rate is below average. The “stuff” he throws actually projects to be below-average for swinging strikes… but above average for strikeouts. Nola uses his sinker (and four-seamer) to get ahead in the account and then throws his curveball almost half the time in two-strike counts to put batters away. Just because his overall whiff rate isn’t high doesn’t mean he’s not capable of sustainably striking hitters out.
Okay, so if swinging strike rate has the potential for missing out on important aspects of pitching or mischaracterizing certain pitchers (like Nola), is there a better stat available for predicting strikeouts? Why yes, in fact, there is: strikeouts.
While swinging strikes feel like they’re better because they are newer, seem more advanced, and stabilize very quickly, strikeouts themselves stabilize very quickly are composed of both types of strikes. Of course they’re not perfect either, but if you were only able to use one of the two to predict future strikeouts, the correct decision is to use actual strikeout rate every single time.
I ran a quick study to test the predictive nature of each of these stats. I looked at all starting pitchers since 2008 with at least 400 batters faced in consecutive seasons (a total of 777 pitchers). I then looked at the correlations between their strikeout rate and swinging strike rate in the first year and their strikeout rate in the second year. The results:
While both do an excellent job predicting future strikeout rate, actual strikeout rate does a better job than swinging strike rate does—in large part because it misses on guys like Nola.
Of course, the obvious response to this is “why not use both?” And that’s a great question. To answer it, we need to ask another question: “How much additional value do swinging strikes add once we know a pitcher’s strikeout rate?” Rather than re-invent the wheel, Matt Swartz ran a study years ago at Baseball Prospectus that Eno Sarris of FanGraphs referenced in a recent tweet when wondering about Nola. Swartz too, of course, found that swinging strikes are great on their own, but once you account for actual strikeout rate… well, not so much:
… for pitchers with the same strikeout rate the previous year, a pitcher with one percentage point higher swinging-strike rate only will have a 0.12 percentage point higher strikeout rate, which is not statistically significant. The value added from this information is virtually useless…
In other words, the value added by knowing the swinging-strike rate when the strikeout rate is already known is less than a tenth of a percent of the differences in players’ strikeout rates the following year.
While my rant against wOBA a few weeks ago largely amounted to “wOBA is a shortcut that doesn’t add anything valuable to a conversation about comprehensively projecting players,” I don’t completely think that’s the case with swinging strikes. They’re certainly not a shortcut, and they can give us insight into what type of pitcher we’re dealing with and how they accomplish what they do. As the math plainly implies, though, they are extremely overrated, as many things that are shiny and new are when people don’t take the time to actually study them. I do believe swinging strikes can add some value to projecting future strikeouts, it’s just that the amount of value they add is incredibly small because strikeouts themselves have so little noise to begin with. And if you’re actually using them instead of plain old strikeout rate, well, you’re straight-up doing it wrong.
Rising… and Underrated
Ozzie Albies, 2B/SS, Atlanta Braves
Albies is the latest top prospect call-up, promoted to be the everyday second baseman for the Braves. He’s not a great hitter, but he’s toolsy and can be valuable for DFS purposes. Most importantly, he plays to his strengths well. He has very little power, and so he hits plenty of groundballs and line drives. This allows him to spray the ball and use his speed to post an above average rate of hits on balls in play. And, of course, crucial for contact hitters like Albies is actually making contact. Albies isn’t elite in this regard, but he does project to be slightly above average. The lack of power and walks makes him a below-average hitter overall (THE BAT projects a .305 underlying wOBA), but his plus speed helps him make up for it from a fantasy perspective with steals.
Hitting eighth in the National League (in front of the pitcher) will limit his stolen base upside to an extent, but his dual eligibility at two shallow positions and almost-free price ($2,200 on DraftKings thus far) makes him a viable and appealing punt in the right matchups on the right slates.