Sabermetric Series, Part 5: Pitcher Evaluation
Welcome to the fifth and final edition of this Sabermetric Series. It’s time to look beyond the basic pitching metrics and dive into some of the best tools at our disposal for pitcher evaluation. Here we will cover batted balls, quality of contact, and plate discipline. Wait, what’s that you say? We already did that? Well, my sweet summer child, we have covered such things for hitters, but not pitchers! The metrics are the same, but how we look at them and utilize them are much different. These stats can be every bit as important in justifying a pitcher’s performance as FIP or SIERA, so let’s get going.
Batted Ball Distribution
We covered batted balls for hitters way back in Part 1. However, we look at things much differently through the pitching lens than we do with hitters. Line drives are a great thing for hitters, but for pitchers. It’s what you try to avoid. Ground balls are good … but not as good as fly balls. To reiterate from Part 1, the average BABIP on a ground ball is .241, while it’s just .130 on fly balls. Some pitchers can maintain very high GB or FB rates throughout most of their careers, and that can make FIP and xFIP unreliable. When you see a pitcher with a 3.50 ERA but a 4.50 FIP, look at his batted ball distribution. If he has, for example, a 47% FB% — there’s a reason he’s beating his FIP, and it could be sustainable.
Different pitchers can have success being extreme ground ball pitchers or extreme flyball pitchers. There is no one formula that works for everyone. If you can consistently induce 45%+ ground balls, you’re going to help yourself maintain a good BABIP (presuming your infield defense isn’t horrendous). It isn’t everything, but it is a good thing. Flyball heavy pitchers can also consistently limit their BABIP, particularly with good outfield defense behind them. For example, Marco Estrada befuddled many a fantasy player in 2015-16 with ERAs much lower than his FIP. He did this with a FB% around 50% and an elite pop-up rate. It’s important to take into account the venue in which a flyball-heavy pitcher calls home, however. Flyballs are obviously the type of batted balls that can turn into home runs, so extreme flyball pitchers can run into homer issues pitching in small parks.
We also mustn’t overlook IFFB%, or pop-ups. As detrimental as they are to hitters, on the flip side they are money for pitchers. They are automatic outs, and it doesn’t get any better than that. If you look at the 2017 IFFB% Leaderboard, you see some very successful seasons that coincide with that stat. Only one out of the top 10 in IFFB% finished with a BABIP over .300, with the average BABIP among them being just .278.
Quality Of Contact
Soft%/Med%/Hard% is a good complementary tool for evaluating pitchers. As stated in Part 1, the averages in 2017 were 18.9%/49.3%/31.8%. A quick look at some of the Soft% leaders from 2017 (hello, Corey Kluber) confirms that inducing soft contact leads to less hard contact and, as Borat would say, great success. However, allowing a bit too much hard contact isn’t quite a death sentence. In fact, the two pitchers that allowed the highest Hard% in 2017 — Robbie Ray (40.4%), Chris Archer (39.4%) — had great seasons. They were able to overcome an abundance of hard contact by striking out a lot of batters and working out of trouble. The next two on the list — Rick Porcello (38.3%), Ricky Nolasco (37.6%) — do not strike out many batters, and their results on the season were considerably worse. Pitchers that induce a great deal of soft contact and pop-ups are generally going to wind up with good results, regardless of strikeout rate.
Personally, I don’t use as many plate discipline numbers for pitchers as I do for hitters. There are two that I look at quite a bit, though, and those are O-Swing% and SwStr%. The higher the chase rate, the more a pitcher is getting a hitter to expand the strike zone and potentially make poor contact. Anything over 30% is pretty encouraging. With swinging strike rate, anything over 10% has my attention. Chris Sale maintained a terrific 36.2% O-Swing% and 14.9% SwStr%, which led to him striking out 308 batters last season.
One of the best aspects of using plate discipline stats in your analysis is that you can look at them in smaller samples and be able to rely on them a bit more than simply K% or ERA. In fact, some of these numbers can be predictive to an extent. For example, if you have a starter who has thrown 50 innings and has managed a 30% K%, is his stuff really that good? If he has a SwStr% of just 8% and a 25% O-Swing%, odds are those strikeouts are coming down.
You can also look at Zone% and F-Strike% when evaluating walk rates. Neither stat individually is enough to guarantee a pitcher will move forward with good or bad control, but it can help you tell if a big change in a walk rate is legitimate or anomalous. If a pitcher has suddenly cut his walk rate in half, look at his F-Strike% and Zone%. Is there a notable change there? If not, he probably hasn’t really made an adjustment, and he will revert closer to his career rate over time.
F-Strike%, or First Pitch Strike Rate, tells you the percentage (per batter) that a pitcher throws the first pitch for a strike. A higher number indicates strong control/command and an aggressive approach on the mound, while a lower number indicates a lack of control. The average is around 60%, and any pitcher with a F-Strike% over 65% is pretty much a lock for a good walk rate. Clayton Kershaw led all starters in 2017 with an elite 69.4% mark — his BB/9 was 1.54. Josh Tomlin, for all his flaws, was second in F-Strike% at 68.6%. His BB/9 was a microscopic 0.89. Conversely, anything below 58% is pretty poor and will most likely indicate a pitcher is going to be prone to walks.
Zone% is simply the percentage of pitches a pitcher throws in the strike zone. The average is around 45%, with the 2017 leader being German Marquez at 53.2% and the lowest mark going to Wade Miley at a measly 35%. When you combine Miley’s 35% Zone% and 53.7% F-Strike%, it’s no surprise he posted a 5.32 BB/9. Looking at Zone% by itself doesn’t do you much good, though, which is important to bear in mind. Pitchers can be very effective pitching out of the zone and getting batters to whiff or make weak contact. Look no further than Dallas Keuchel, whose 37% Zone% was the third-lowest mark in MLB. His F-Strike% was a mediocre 60.5%, but he walked just 2.90 BB/9 and wound up with a 2.90 ERA over 145.2 innings. It’s not always a good thing to pound the zone, especially without true swing-and-miss stuff.
With that, we wrap up this Sabermetric Series. I hope you’ve enjoyed it, and if there is anything from this series you want to discuss with me, or if there is something I failed to touch on, reach out to me @NathanDokken on Twitter. I’d be more than happy to chat with you. It is my hope that you can utilize these metrics in your own personal analysis, and perhaps even be a better player because of it.