Yesterday, David Appelman unveiled our new heat maps, and I love them. As I noted yesterday, the linear weights graph is especially awesome, as it allows you to see where a particular hitter or pitcher is having success, and not just settling for incomplete answers like outcomes on balls in play, which ignores all the variable outcomes that happen on takes, or on swings that don’t put a ball in play. Being able to highlight a player’s overall performance on all pitches is a big step forward for the heat map concept in general.
But beyond even just individual players, there is some really fascinating information available. Based on his discussion with Chris Young, Eno got David Appelman to generate some great charts of league-wide averages for groundballs and home runs. And now, with the release of the heat map tool for all pitches on a league-wide basis, we can begin to say some pretty interesting things about pitching to specific parts of the strike zone.
When given access to the league-wide heat map, my first instinct was to look up the linear weight value of pitch locations. For the 2014 season, that looks like this.
Nothing too revolutionary here, though. Pitches in the zone are better for the pitcher than they are for the hitter, with pitches in the very middle of the zone being not quite as good for the pitcher as pitches on the edges. But, yeah, anyone who has watched baseball knows this. Pitchers should throw strikes, and when they don’t, it works out poorly for them: News at 11.
So, instead, we have to drill down a bit further to find anything interesting. For starters, instead of looking at all batters versus all pitchers, we want to just look at batter handedness, so that one chart isn’t representing both inside pitches and outside pitches in the same location. Because the heat map tool lets you choose what kind of batter/pitcher handedness match-ups you want, we can go down to specific match-ups and look for location information based on those match-ups.
For now, let’s start with RHP vs RHB, since this is the most common match-up in baseball. And because larger samples are better, let’s expand from just 2014 data to include the last few years as well, so we’re now looking at all pitches from 2012 to 2014 thrown by a right-handed pitcher to a right-handed batter. Here’s what that map looks like.
This is much more interesting. Here, we see that the pitchers have far more success pitching on the outer third than they do when they try to come inside, with the down-and-in area being even better for the hitter than elevated pitches over the heart of the plate. This is consistent with what we saw when we looked at Mike Trout’s heat map yesterday; you do not want to throw Trout anything down-and-in if you can help it. While he’s exceptionally dangerous there, this data does suggest that pitching inside is, as a general rule, not as effective as pitching away, though of course one almost certainly needs to do both in order to avoid being predictable.
But this doesn’t help us answer the question of why the outer third, and specifically the lower part of the outer third of the zone, is so strongly positive for the pitchers. The linear weights chart gives us the result but not the process, so instead, let’s look at the charts that do measure the process. First off, here’s the rate at which right-handed hitter’s swing at pitches from right-handed pitchers, and we’ll switch to the 5×5 grid in order to show the differences a little more clearly.
The down-and-away area of the strike zone is the only one where batters take more often than they swing. Hitters are much more willing to go after pitches on the inner-third than they are on the outer-third, and the down-and-in swing rate is 15 percentage points higher than the down-and-away swing rate. Hitters aren’t stupid, though; they aren’t going to pass up on pitches they think they can drive, so if they are taking a majority of pitches in that part of the zone, it follows that either they think down-and-away pitches are likely to be called balls, or that they just can’t really do anything with pitches in that area to begin with, so they keep the bat on their shoulder and hope for the best.
The charts seemingly suggest that the latter is true. Here’s their contact rate by swing locations:
Down-and-away is the only in-zone area where RHBs make contact less than 80% of the time when they swing at a pitch from an RHP. There’s no other part of the zone that is even close to having that low of a contact rate, and additionally, the contact rate drops even more dramatically if you miss further down, further away, or further down-and-away. There is no location, in-zone or out-of-zone, that offers lower contact rates than pitches down and away.
And what about when they do hit the ball? Again, no area offers a more meager return on investment than down-and-away pitches. Here is the league’s RHB/RHP Isolated Slugging Per Pitch:
Hitters drive the ball on pitches middle-in, but on pitches down-and-away, there’s basically no power whatsoever. So on pitches down-and-away, hitters don’t make contact when they swing, and when they do make contact, they don’t drive the ball with any kind of authority. No wonder they don’t swing at those pitches; there’s no real reward for doing so.
Now, we have to keep in mind that we’re only looking at one variable here. A pitches location is certainly important, but we can’t just extrapolate from this that every pitcher should just throw every pitch down-and-away. Realistically, the down-and-away area is probably disproportionately represented by breaking balls, as RHPs want to bury their sliders in that area when facing an RHB. Pitchers can’t live on a steady diet of only down-and-away breaking balls or else hitters will simply stand closer to the plate and sit on a pitch they know is coming. Also, their elows would explode, even more than they are now. Pitchers have to pitch to different parts of the zone, and with different pitches, in order to maintain some element of surprise.
But perhaps the fact that the down-and-away area — and just pitching away in general — is so strongly positive for the pitcher suggests that pitchers are still not going there enough. In a perfect world where the hitters and pitchers keep adjusting to each other’s adjustments, we would expect these adjustments to eventually find an equilibrium. That doesn’t exist right now. Right now, hitters basically can’t hit pitches down-and-away, and they’re much worse on pitches away than pitches in.
At the very least, the data strongly suggests pitchers should not pitch inside nearly as often as television announcers tell us they should. Pitch inside to keep hitters honest, but if you want to get them out and avoid giving up hard contact, you want to pitch outside, not inside.
Dave is the Managing Editor of FanGraphs.