Guerrero, Andrus, and Swing%

One of my favorite stats pages on FanGraphs is the Plate Discipline Leaderboard. In it, you can find out which hitters swing at pitches out of the strikezone (O-Swing%), make most contact when swinging (Contact%), or see the most pitches in the zone (Zone%). In particular, Swing% tells us which batters swing at the most pitches or the fewest pitches. It should not be surprising that Vladimir Guerrero is the leader in this stat this season, swinging at 60.7% of all pitches. On the other end of the leaderboard, his Rangers’ teammate Elvis Andrus is 6th this season in the least percentage of pitches swung at with 36.9%.

I was curious to see how Guerrero and Andrus differed in Swing% based on different pitch types: fastballs, sliders, curveballs, and changeups. I modeled each batter’s Swing% vs. each pitch type by handedness and plotted heat maps for each one. Turns out I came up with 16 graphs, so let’s take a look at four of them at a time. The first four are Guerrero and Andrus against RHP and LHP fastballs:

Guerrero saw 2335 RHP fastballs and 904 LHP fastballs since 2007 while Andrus saw 1522 RHP fastballs and 541 LHP fastballs since his debut. The levels on the right can be read as percentages, so 0.8 indicates swinging at 80% of pitches. Guerrero loves to swing at fastballs from both hands, swinging at 80-90% of fastballs up and in while inside the zone. The centers of these fastball hotzones are similarly located for Andrus, but he swings at far fewer fastballs, maybe topping out at 65-70% in his hottest spots. Let’s look at the next four, which are against RHP and LHP sliders:

Guerrero saw 1040 RHP sliders and 174 LHP sliders since 2007 while Andrus saw 429 RHP sliders and 88 LHP sliders since his debut. Again, Guerrero hacks at a lot of sliders, particularly low and inside sliders from LHP. It seems that Andrus is also pretty vulnerable in swinging at low LHP sliders, but many of these are low and outside instead for the young right-handed hitter. Let’s look at how the teammates swing at RHP and LHP curveballs:

Guerrero saw 441 RHP curveballs and 208 LHP curveballs since 2007 while Andrus saw 262 RHP curveballs and 105 LHP curveballs since his debut. Similarly, both Guerrero and Andrus swing more at LHP curveballs than they do against RHP curveballs. Remember, these plots are looking at Swing% and are not indicative of whether the result of the swing was a swinging strike or an extra base hit. However, you can safely assume that a low breaking ball out of the zone is not a wise pitch to swing at (well, except that Guerrero is notorious for making solid contact off pitches out of the zone, but that’s for another post). Finally, let’s look at Guerrero and Andrus swinging against RHP and LHP changeups:

Guerrero saw 313 RHP changeups and 278 LHP changeups since 2007 while Andrus saw 237 RHP changeups and 212 LHP changeups since his debut. The colors in these plots look similar to that of fastballs, except that the epicenters of the hot swing spots are lower for changeups than for the high fastballs. Again, Guerrero isn’t afraid to swing at inside RHP changeups, swinging at 90% in some areas, while Andrus lays more of these pitches off, swinging at about 50% of changeups throughout the strikezone.

A lot of interesting questions could be asked from here in terms of comparing Guerrero and Andrus. For instance, how often does Guerrero make contact off of low sliders compared to Andrus when he swings? How much damage does Guerrero make off of changeups down the middle compared to Andrus? Is Guerrero swinging at too many pitches or is Andrus swinging at too few? This season, Guerrero has made contact 80.6% of the time he swings, while Andrus, although swinging at many fewer pitches, makes contact 88.4% of the time when he does.

A quick look at pitch type values can also tell us which hitter is more successful against which pitch types. Obviously, Guerrero has much more power than Andrus does and is particularly effective at hitting curveballs and changeups, with a wCB/C of +6.85 runs and a wCH/C of +4.68 runs — good for 1st and 2nd in the majors this season. However, the one pitch that Guerrero is worse at hitting this season is the slider, with a wSL/C of -0.52 runs (he has been more successful in the past).

Much more information can be gleaned if we look at contact, batted ball, or SLG% plots. For now, it’s fun to marvel at visualizations of vastly different approaches in plate discipline.



Print This Post



Albert Lyu (@thinkbluecrew, LinkedIn) is a graduate student at the Georgia Institute of Technology, but will always root for his beloved Northwestern Wildcats. Feel free to email him with any comments or suggestions.


Sort by:   newest | oldest | most voted
Lucas Apostoleris
Guest
5 years 11 months ago

These posts are so awesome. I like the concept of showing the two extremes from the teammates.

Steve C
Guest
Steve C
5 years 11 months ago

Is there a potential bias built into the data when looking at these sorts of graphs? My thought is that Guerrero loves some high and inside fastball because that is where they tend to be thrown, not that he has an actual preference towards them.

Is it possible to break the zone down into smaller areas (5, 9, or 16) and normalize the data?

Patrick
Guest
Patrick
5 years 10 months ago

The colors represent percentage swung at, not total number. Now it could be that he’s used to seeing inside high fastballs, which ups his percentage a tad over other fastballs, but the bias would be slight.

pack
Guest
pack
5 years 11 months ago

Can you do something with the result of a specific pitch, as a standard deviation from their normal pitch type values?

Like is there a zone where andrus hammers curveballs, and other places he just hits them for singles? Or do sample sizes start getting to small when you break into pitch types in a single year?

adohaj
Guest
adohaj
5 years 11 months ago

Great post

It really jumped out at me how much Andrus chases that slider for Andrus’ sake I hope pitchers don’t read this

Andy
Guest
Andy
5 years 11 months ago

really, really cool. Thanks for this post

RMunkee
Guest
RMunkee
5 years 11 months ago

As a longtime Angels fan, I’m under the impression that Vlad does VERY well against LOW pitches, either inside, or over the plate. ( Actually, a little lower than the strike zone, which I assume your boxes are.)

Is there a source to find a “heat map” of such a thing? Thanks.

Victor
Guest
Victor
5 years 10 months ago

You should write more articles on my team haha

wpDiscuz