Was Gio González Falling Behind on Purpose?

When you’re watching a baseball game, there are few things as nerve-wracking as seeing your favorite team’s pitcher consistently fall behind hitters. You know intuitively that the better the count is for the hitter, the better chance there is he’ll see a pitch he can slug. Broadcasters often love to talk about first-pitch strikes and their importance in both “setting the tone” of an at-bat and keeping pitch counts low. These are all valid notions — in 2019, the league-wide wOBA when the pitcher was behind in the count was .432. When the pitcher was ahead or the count was even, that mark was .269. That’s about the same difference as there was between Mike Trout and Orlando Arcia, the worst qualified hitter of last season.

Nearly everyone who threw at least 1,500 pitches in 2019 performed worse when behind in the count, with the exception of Tigers starter Jordan Zimmermann, who was just bad regardless of the situation. But just because someone falls behind in the count doesn’t mean he’s a lost cause. Even when at a disadvantage, some pitchers hold their own just fine. Here were the 10 best pitchers when throwing from behind last season.

By and large, that’s a list of good pitchers. However, there is an outlier here in Gio González. Not because he isn’t a good pitcher, mind you. The veteran lefty, who signed with the White Sox over the winter, held a 3.50 ERA (79 ERA-) and 4.04 FIP (90 FIP-) over 87.1 innings with Milwaukee last season. He doesn’t stand out because of a lack of skill level. He stands out because of how often he’s behind compared to the other pitchers on this list.

Part of the reason many of the above pitchers have decent numbers when behind in the count is because they rarely find themselves in those situations to begin with. Walker Buehler, for example, had the 14th-lowest percentage of pitches thrown from behind in the count in baseball at 22.7%. Jacob deGrom, Shane Bieber, and Zach Eflin weren’t far behind him. González, however, had the highest percentage of pitches thrown from behind of anyone who threw at least 1,500 pitches last season at 35.6%. The 3.2-point difference between him and second place is the same as the distance between second and 27th. Those who did throw from behind with similar regularity couldn’t come close to limiting damage the way González did.

I’ve expanded the above list to the 50 best-performing pitchers when behind in the count, and then I plotted them according to the rate at which they actually found themselves in that situation. González is in yellow, all by himself.

There are a few ways one might choose to interpret this. One takeaway could be that González simply got lucky. He’s nibbling too much or is just plain wild, but either way, he’s flying too close to the sun. If you’re a White Sox fan, this might even spook you into thinking this signing was a mistake, that he’s bound to regress hard. I don’t really fault anyone for feeling that way, but I don’t think this is that simple. I think González knew exactly what he was doing. I think he had a plan, and that plan involved sometimes falling behind in the count intentionally. And I think it worked.

Consider, for starters, the fact that González had never previously been this wild. His zone rate had never been below 40.5% before 2018, but last year it was 32.6%, the lowest in baseball. Similarly, his first-pitch strike rate had once been excellent, never dipping below 55% between 2012-17. In 2019, it was 48.1%, the lowest in baseball by five and a half points. Here’s what those two dips look like in relation to his own career, as well as the MLB average.

Again, you could interpret this is as someone completely losing the zone as he entered his mid-30s, which would be an enormous red flag. That kind of dramatic drop in strike-throwing looks more intentional to me though, especially considering when it began to take shape. In 2018, González was an Aug. 31 waiver deadline addition by Milwaukee, a team that has come to be known for its pitching innovations. As soon as he became a Brewer, this new version of him emerged.

If we accept, for the sake of argument, that this sharp decrease in strike-throwing was part of a larger scheme, the question then becomes why? Why subject a pitcher to the risks involved with forfeiting count leverage when his own opposing wOBA numbers regress when he falls behind, and when the league-wide splits so clearly advise pitchers get ahead early and often?

Let’s address González’s own splits first. His opposing wOBA does take a 49-point hit when he falls behind, but remember that there is always inherent bias in those splits. I’m using Baseball Savant data for this piece, and Baseball Savant reports 3-2 counts as batter-friendly. That means all walks are automatically getting fed into one side of the data, and the majority of strikeouts are getting fed into the other. That lone fact makes using wOBA to gauge whether a pitcher is better or worse throwing from ahead or behind a bit tricky.

Is that enough to account for the gap in production between pitcher-friendly or even counts and batter-friendly counts? Certainly not. While pitchers are inherently surrendering all of their walks when behind in the count, they’re also still getting hit much harder. In 2019, hitters hit .236 and slugged .395 (a .159 ISO) when the pitcher was ahead or the count was even. When the batter was ahead, those numbers jumped to .295 and .540, an ISO of .245.

That’s what makes González interesting. Here are his opponents’ numbers when González was ahead or even as well as when he was behind.

That power explosion the rest of the league suffers from when falling behind never reached González. The slugging percentage he allowed when behind in the count was the second-lowest in the majors, as was his batting average allowed. González could afford to fall behind because he knew he could still keep the ball in the park, and more likely, could keep hitters from getting aboard at all.

The secret to this magic act is González’s changeup. Decidedly his fourth pitch over the first half of his long career, he’d been gradually increasing its usage for years before making it his No. 1 offering in 2019, throwing it 31.7% of the time, a nearly nine-point jump from the previous season. That changeup was in the zone just 30.8% of the time he threw it, but that didn’t stop him from throwing it aggressively in batter-friendly counts — when a ball was theoretically most harmful, but also when hitters least expected it to see it. In 2019, pitchers league-wide threw an off-speed pitch when behind in the count just 12.4% of the time, compared to 66.1% fastballs. González, meanwhile, threw his change in 39.1% of batter-friendly counts, completely throwing off hitters expecting a fastball to punish. Batters still unsurprisingly torched fastballs when they got them, but when they got a changeup ahead in the count, they hit just .098 and slugged just .196.

You can see this in action in González’s final start of the season when he faced the Rockies. Ryan McMahon works a 3-1 count and gets a middle-middle change, and he completely misses.

Here’s another 3-1 changeup to Drew Butera, and another whiff.

Then two more in an at-bat against Charlie Blackmon — one on 1-0, the other on 3-1.

If watching a pitcher consistently fall behind is a grind, watching hitters repeatedly fail to take advantage of those situations can be even more maddening. That’s the reality González forced upon fans cheering both for and against him last season.

Whether González takes this experiment with him to Chicago remains to be seen, but I’m less interested in how long he can keep this high-wire act alive than I am in what this could teach us about helping other pitchers. González is 34, has never been a control artist even at his peak, and now boasts an average fastball velocity below 90. If he bought into the philosophy that he had to use his fastball to get back into counts, he would get annihilated. Instead, he bucks the trend and simply trusts his best pitch to get him out of trouble, and it works.

Could this work for other pitchers? Consider, for example, Patrick Corbin. In 2019, when Corbin was ahead or the count was even, he allowed an opponents’ wOBA of just .190, second-best in the majors. When he fell behind, his opponents had a wOBA of .464 — the 22nd-worst in the majors. That was the largest difference by any pitcher by a good margin. Why such a dramatic shift? Because even though his slider is far and away his best pitch, he almost completely abandons it when he gets to 2-0 and 3-1, and doesn’t even keep it as a primary option when he goes 3-2. Compare Corbin’s count breakdown with that of González.

The only reason for Corbin not to keep throwing sliders when he falls behind is that he can’t trust it to be a strike when he needs one, but with a zone rate of 31.9% and an opponents’ wOBA of .202, his slider is almost a dead ringer for González’s changeup. And considering Corbin threw 26.9% of his pitches from behind in the count last year — more than 84 of the 144 sampled pitchers — there should be little downside to making his best pitch a featured weapon in more situations.

As a table earlier in this piece shows, pitchers are steadily decreasing the number of strikes they’re throwing, which means learning to pitch from behind in the count will become a more important skill with each coming year. There’s a chance González’s change in approach, intentional or not, doesn’t work beyond 2019. But there are lessons to be learned from it that could impact other pitchers for years to come.