Nathan Ray Seebeck-Imagn Images
If you’re a major league hitter, you’ll reach a two-strike count. Not every time – baseball isn’t an every time game – but frequently, consistently, inevitably. In those two-strike counts, you’re going to see sliders. Again, not every time, but frequently. A quarter of two-strike pitches in the majors this year have been sliders of some variety. Pitchers are no dummies, and they know where their bread is buttered.
The worst thing that could happen with those two-strike sliders you’re bound to face? A strikeout, obviously. But bad news: There are going to be strikeouts. Again, not every time, but strikeouts are just a fact of life in baseball these days, and 21% of two-strike sliders have resulted in strikeouts this year. Not in the plate appearance – on that pitch specifically. No wonder pitchers throw so many of them.
With all that in mind, here’s a statement I’m sure you’ll agree with: A good way to get better at hitting is to stop striking out on two-strike sliders. I mean, this isn’t rocket science. Striking out is bad. Doing it less is good. Thank you for coming to my TED talk.
Oh, right, I guess I still have to tell you what this article is about. Let’s talk about a player who made a heroic change. Early in his career, he did a fair job protecting against sliders with two strikes (15.4% putaway rate on two-strike sliders). In 2023, though, things took a turn; he struck out on 20% of the two-strike sliders he saw. This year, however, he’s defending against them better than ever. No player in baseball has gone down less frequently against two-strike sliders than our mystery man’s 8.6% clip. Pitchers simply can’t get him out.
He’s putting up a glorious 118 wRC+ and striking out less often than last year. There’s just one problem: Our blind item player is Yandy Díaz. And while he’s having an acceptable season this year, it’s miles worse than last year’s campaign, when he was swinging and missing at all those two-strike sliders. He’s not even doing better with two strikes. His batting average, on-base percentage, and slugging percentage in two-strike counts have all declined this year, both against sliders and overall.
If this feels like quite the conundrum, that’s because it is. The key development of baseball over the past decade has been pitchers increasingly hunting strikeouts. I don’t need to show you one of those charts of slider rate over time; all you have to do is watch a game. They’re using the pitch more because it works, and one of the key ways it works is by missing bats in advantageous counts. Sliders are the best strikeout weapon in modern baseball.
However, the other side of this is an inconvenient truth for people who like balls in play and action. Let’s take Díaz as an example. He’s completely changed his behavior against sliders this year as compared to last year. It’s not a pitch recognition thing. He swung at two-strike sliders off the plate (in the Chase and Waste zones defined by Baseball Savant) 23% of the time last year, and that’s up to 26% this year, each in small samples. He’s defending sliders over the plate at roughly the same rate: 98% last year, 94% this year. He’s not even getting fooled less by perfectly placed sliders just off of the edge of the zone; he swung at 78% of those last year and 82% so far this year. No, Díaz made a completely different change: He just stopped missing.
Last year, he swung at 71 two-strike sliders that weren’t over the dead middle of the plate. In other words, these are the pitches that were, more or less, executed the way the opposing pitcher wanted. He came up empty on 35% of those swings. That’s not disastrous or anything – the league average is around 37%. This year, he’s down to a 14.5% whiff rate, which is the lowest in baseball, just a hair ahead of contact god Luis Arraez, who has gone more than a month without striking out.
Last year, Díaz whiffed on 27% of down-the-middle sliders on two strikes. This year, he’s at 3.6%, one whiff on 28 swings. We don’t have bat tracking data for 2023, which is a shame, but there’s an easy assumption to make here. How do you keep your swing decisions unchanged and yet make contact at a far higher rate? By taking a less violent swing. You can see it in the numbers. He’s hitting the ball meaningfully softer when he offers at two-strike sliders. His hard-hit rate when he puts one in play has dipped from 54% to 36%, and he’s had over roughly 100 balls in play in each year, so not a tiny sample.
Hard-hit rate is hardly the only change here. His average exit velocity and 90th percentile exit velocity are way down on these swings. His ground contact, in particular, is absolutely abysmal. We’re talking 83.4 average exit velocity, .174 slugging percentage miserable. He’s chopping the ball into the ground rather than taking a strikeout, which is a good bargain – only we’re talking about 23 additional grounders this year, which is a ton. This particular change in Díaz’s game has permeated the rest of his offensive approach. He’s performing worse against every type of slider despite making contact with them more often, and it’s all due to contact quality.
If you’re looking for it in xwOBA terms, he punished the sliders he put in play last year to the tune of a .506 xwOBA. This year he’s down to .376. That’s the difference between Giancarlo Stanton’s production on contact and Edmundo Sosa’s. Saving the odd strikeout here or there can’t possibly make up for that kind of swing.
I have no idea if this change is intentional. It’s certainly striking, though, because the change in behavior seems limited to breaking balls. Against fastballs, very little has changed. There, his hard-hit rate is essentially unchanged, and while he’s hitting the ball on the ground a bit more often, that had to be expected after his career year in 2023. Likewise, he’s basically the same player when he swings at changeups and splitters; he’s actually hitting those pitches a bit harder this year, though in a small sample. He’s also getting better results. But against bendy stuff – mostly sliders, but curves as well – everything has gone wrong.
Here’s the dirty secret about sliders: As much as the swings and misses are appealing, batters changing their approach and sacrificing contact quality works just as well for the defense. Pitchers will gladly sacrifice a few strikeouts if it means someone with Díaz’s raw power is slapping the ball on the ground. Here’s another way of looking at it: Díaz has seen 51 sliders this year where our PitchingBot model thinks that an average hitter would hit a home run at least 2% of the time. You can think of those as crushable sliders; the average home run likelihood of all sliders he’s seen this year is only 0.6%. He’s hit one homer on those 51 pitches. Overall, his total production on these sliders – and remember, these are the worst he’s seen all year – is 1.5 runs above average relative to a random pitch. That’s pretty miserable.
For comparison’s sake, he saw 61 last year and hit three homers on the way to being 5.1 runs above average. There are a few ways to beat pitchers who throw you too many sliders. First, you can spit on the ones that aren’t in the zone. We’ve already established that Díaz hasn’t changed his swing rate, though, so that one’s out. Second, you can punish the bad ones. Announcers talk about hanging sliders all the time. It’s a real risk! If you leave one sitting up over the plate, good hitters can crank it out of the park. But they’re a lot less likely to do that if they’re focused heavily on making contact. The swing that you use to make contact with a good slider and…
