Gio González has a very particular set of skills. No, it’s not rescuing his kidnapped daughter — it’s something far more useful for baseball. Or, it was — until 2020. González, and Steven Matz as well, are simply otherworldly when it comes out to striking out opposing pitchers.
That probably seems weird to you, because those guys aren’t exactly prolific strikeout artists. Take a look at the top 10 pitchers in pitcher strikeout rate (since 2015, minimum 100 PA):
That’s eight pitchers with high-octane, face-melting stuff…and González and Matz hanging out in rarefied air.
It seems like it should be random. Pitchers strike out a ton — that’s basically their entire life at the plate. Maybe you can sprinkle in a curve or two, but for the most part, you go up there and sling it and they sit down. That was my assumption, at least, before seeing this leaderboard. (Well, before seeing this leaderboard and reading this old Jeff Sullivan article.)
Gio isn’t new to this. In 2012, he led the league while setting a record for single-season pitcher strikeouts. In 2017, he led the league again! He was fourth in 2016, eighth in 2018 — it’s not a fluke. Some of that is volume — he pitched full seasons in the NL in each of those years, and that’s a prerequisite; there’s a reason there’s no Justin Verlander on this list.
But the raw strikeout totals aren’t what’s so impressive. It’s the rates — 51.7% for Matz, goodness gracious. And 49.2% for Gio, just as hard to imagine. Take a look at that table again, with a column added for non-pitcher strikeout rates over the same time period:
|Pitcher||Pitcher K%||Non-Pitcher K%|
Bumgarner is kind of in the same boat, but for the most part the way to be good at striking out opposing pitchers is to be good at striking out opposing batters. That’s just so obvious — how could it not be true?
I wondered if González and Matz were doing anything noteworthy to get to their strikeouts. Are they always in the zone? Never in the zone? Are they breaking ball crazy? I wanted to know, so I scraped every pitch that both of them have thrown to a pitcher since the beginning of the Statcast era. Whatever they’re doing, I thought, we’ll find it in the data. Easy as that — right?
Both González and Matz start things off on a good note. González has a first strike rate of 67.5% against pitchers, Matz a near-identical 66.1%. First strike rate, as a refresher, is the percentage of 0-0 pitches that end with a strike or ball in play. That’s high, but not dizzyingly so. The league-wide first strike rate was 60.1% this year.
Wait a second — are their rates even that good? After all, every pitcher is a candidate to get pitched more aggressively. The overall first strike rate has a bit of Mike Trout and Joey Gallo in it; the pitchers-only population most certainly does not. And yeah — neither stands out. The overall first strike rate with a pitcher at the plate in the same time period was 70.4%. Our heroes are actually less aggressive about getting ahead than the average pitcher.
Are they less aggressive because they’re leaning on secondary pitches more? After last week’s study, I very much had that on the brain, so I took a gander. Aaron Nola came in 10th in our top pitcher-pitcher strikeout rates, and he’s a prolific user of the ambush curve. Could that be our heroes’ strategy?
Again, nope! Matz checks in at 26.1% and González at 26.4%, while the league sits at 30.7% secondaries over the same period. Something doesn’t add up here — they’re throwing fewer first pitch strikes despite more fastballs? That certainly doesn’t sound like a recipe for success. I expected to find more or less the opposite. Ah, well, time to keep digging.
Where else can we turn? Maybe zone rate holds a clue. Balls and strikes are one thing — but zone rate is about process, not results. What if the two merry pitcher-killers are doing something unique when it comes to either drowning opponents in strikes or tantalizing them with pitches just off the plate?
Here, we’re starting to see some divergence. Matz serves the ball up on a platter, metaphorically speaking; 60.3% of his pitches are in the zone. His overall rate is 54.1% (using Pitch Info data) — above league average but nothing like the all-out battering he employs here. González, meanwhile, clocks in at 51.2%. He’s far less aggressive than Matz overall, though — for his career against all hitters, he throws in the strike zone merely 45.7% of the time. Both of them up their rates by similar amounts.
Whither the crowd? Frustratingly, the league as a whole threw in the strike zone 56.7% of the time against pitchers from 2015-2019, smack dab in the middle of our two protagonists. For reference, that mark stood at 48.6% against all batters; our guys increased their strike-throwing slightly less than their fellow pitchers, but not by a conspicuous amount.
At this point, I was starting to wonder if I’d ever figure this puzzle out. It’s not the first pitch. It’s not the rate of secondaries, or the zone rate. Did they simply luck into it? Do the two of them happen to have fastballs that pitchers are worse at hitting? Could it just be luck? That seems unlikely given González’s consistency and sample size, but it’s at least possible.
I had one last idea — maybe they’re just focusing more when it counts. Maybe 0-0 pitches against opposing pitchers aren’t particularly consequential. And perhaps, just perhaps, there’s something here. When the count hits two strikes, Matz and González mean business. Matz finished the job with 42.7% of his two-strike pitches — in other words, he got a swinging strike, called strike, or foul bunt 42.7% of the time that he threw a pitch with two strikes. He didn’t end 42.7% of two strike pitches with a strikeout — this is better than that, because a foul ball here counts as a failure, but results in another two-strike count.
González was behind him at 37.1%, but both were above the league average of 36%. And it wasn’t limited to two strikes, either: when the two of them got to one strike, they stepped on the gas. 54.6% of pitches to pitchers in one-strike counts resulted in two strike counts from 2015-2019. In other words, just over half of the time, a pitcher at the plate took a called strike, swung through something, or fouled the ball off. Matz accomplished this trick on the mound a juicy 64% of the time, and González 56.2%.
It really looks like we might have something here. It’s not just the results that are different — it’s the process. With one strike, both pitchers amp up their strike-throwing. The league as a whole threw a pitch in the zone 57.4% of the time with one strike (all of these rates are to pitchers specifically, I just get tired of writing it every time). Messieurs Matz and González check in at 66.5% and 58%, respectively; and remember, Gio was far below average when it came to zone rate on the first pitch of the at-bat. They both smell blood with one strike and throw something that maximizes their chances of getting to two strikes.
Does this crack the code? I’m honestly unsure. They’re different — but they’re not that different. Dig this deep into any player’s pitch-level history and you might find similar idiosyncrasies. Maybe Matz and González are just subtle geniuses at getting other pitchers to swing through their offerings, or maybe my theory about them hunting two-strike counts is right.
Interestingly, the strategy has, to this point, worked better for Matz than González. Take a look at the lowest wOBA allowed to opposing pitchers over the same sample set, minimum 100 PA:
Matz also has the lowest xwOBA allowed to opposing pitchers in all of baseball. González is no slouch — he checks in at 21st in wOBA and 19th in xwOBA — but Matz truly stands alone. It’s a reminder that striking out your counterpart is nice, but getting them to put the ball into play weakly is nearly as good. Pitchers ran a .243 BABIP and .035 ISO in 2019, after all — maybe the best way to pitch to them is some combination of strikeouts and risking contact in exchange for favorable counts.
Did I learn anything in this meandering article? Sure! Matz is going to miss facing pitchers in 2020 if he gets a chance; 8% of the batters he’s faced in his career have been pitchers, and that number is going to be 0% this year. The consequences of that are greater than you think. In his career, Matz has allowed a .319 wOBA, basically league average. Against non-pitchers, however, it’s been .339. That’s Jakob Junis in 2019, to pick a random AL pitcher.
But mostly, this was just for fun. Gio and Matz are the kings of playing up against opposing pitchers. And despite a comprehensive deep dive, I still don’t really know why. That’s a fun find in a time where I’m desperately short of fun. I’m calling it a win.
Ben is a contributor to FanGraphs. A lifelong Cardinals fan, he got his start writing for Viva El Birdos. He can be found on Twitter @_Ben_Clemens.