The majority of analysis performed on the PITCH f/x data has been from the perspective of the pitcher. This makes sense, as it is really interesting to see how a certain pitch from a specific pitcher moves and how it is put into play. It's much easier to classify pitches from the pitcher's perspective, and there are a host of other "pitcher" things to look at. However, there is another half of the data that hasn't been covered as in depth. Looking at the PITCH f/x data from the hitter's perspective could yield some interesting nuggets of info, so today I'm branching out, spreading my wings, and looking at the hitter's version of the data.

The easiest visual to create for a hitter is a chart showing how pitchers have approached him this season. Below on the left is a chart showing where Vladimir Guerrero has been pitched to this season. The number in each box is the percent of all pitches thrown that went to that area and while it seems that pitchers might be trying to avoid throwing high pitches to Vlad, overall there isn't too much going on here. On the right is a chart that shows Guerrero's BABIP for different regions. This is a much more interesting chart and is closely related to the results on the density chart. There's a very good reason that pitchers would avoid the top third of the strike-zone with Vlad...when he puts those balls in play, he hits .565! Before we call Guinness though, it's worth noting that hitting .565 in this case means going 13-for-23. Because of the sample size issue, reading too much into Vlad's hot zones is misleading, but there are some basic patterns, such as hitting high pitches well and what appears to be a weak area, located down and away from Guerrero.
 

I think these types of charts are fascinating and give you a good idea of a hitter's swing. You can easily pick out where batters feast on pitches and where they struggle. With a bigger sample than what I have right now, you could even have some confidence in your conclusions about those zones. Speaking of bigger samples, here is a chart that shows the BABIP for all RHB this season. Now instead of having 10 balls in play for a box, there are 10,000, which lets you say that low and away pitches appear to give most RHB trouble, not just Guerrero. Below on the right is a BABIP chart for Jason Kendall. Kendall has been anemic at the plate this season, and you can see exactly why when you look at the chart. Inside pitches give him problems, he hasn't done much better on outside pitches, and high pitches, well, he hasn't hit those either. The only place where Kendall has had any success this season is in the lower third of the strike zone, although judging by his density chart, pitcher's haven't figured that out yet.
 

I say that pitchers haven't figured out Kendall's strength yet and avoided throwing him low pitches, but (assuming I'm correct with my assessment of his weaknesses and strengths) do pitchers ever figure out these types of patterns vs. a hitter? How necessary is it to know, and pitch to, a hitter's weaknesses and strengths? Game theory might say that pitching too often to a hitter's weakness would eventually give him an advantage because he would have a good guess on the the location where the next pitch was coming. Whether that advantage would be offset by his inability to hit the pitch is unknown, but you are dealing with Major League hitter. If you gave most hitters the location of the pitch and let them focus primarily on that spot, even if it were a spot where they otherwise had trouble, I think they would be successful. Pitchers have to vary their locations, both in and around the strike zone, to avoid giving the hitter an advantage (duh). In the case of Kendall, and every other hitter I've looked at, pitchers appear to be somewhat varying their locations, although for Kendall, pitchers have thrown more low pitches than high pitches, which cues Kendall to look for more low pitches, and enhances his only strength.

Now with some idea of where pitchers throw to certain hitters and how the hitters respond, lets look at what pitchers throw different hitters. Building on my pitch filter, and some of the earlier work done by Dan Fox, ultxmxpx and Josh Kalk I went through my database and attempted to label every (currently only the ones tracked from 50 feet) pitch in it . Any automated process that attempts to classify pitches is going to have mistakes and mine is no exception, but after comparing the filter's results on individual pitchers to the results I got from manually clustering pitches, I was generally pleased with the results. The filter remains a work in progress (it can't differentiate between a split-fingered fastball and curveball or a 2 and 4 seam fastball and has trouble with certain pitcher's change ups) but the results are pretty good overall.

Here are the MLB averages for how frequently different pitches are thrown. This is for all pitchers vs. all batters in all situations, so it isn't the most telling statistic, but it gives a general sense of how often a fastball (or change up) is thrown.

Pitch             Freq.
Fastball (FB)     0.59
Change up (CH)    0.16
Curveball (CB)    0.13
Slider (SL)       0.08
Unknown (UK)      0.04

Without further ado, here are the batters who have seen the highest and lowest frequency of each pitch, with frequency being the number of a given pitch divided by the total number of pitches that hitter has seen. (Min. of 80 total pitches tracked by the PITCH f/x system.)

Name              Pitch  Count  Total   Freq.
Tony GwynnJr.     FB      92    118     0.78
Robert Fick       FB      66     88     0.75
Reggie Willits    FB     502    673     0.75
Frank Thomas      FB     504    693     0.73
Luis Rodriguez    FB      66     91     0.73
Brad Ausmus       FB     261    360     0.73
Willie Bloomquist FB     122    169     0.72
Scott Podsednik   FB     293    407     0.72
Fred Lewis        FB     117    163     0.72
Jason Kendall     FB     456    638     0.71
============================================
Josh Paul         FB      48    111     0.43
Hanley Ramirez    FB     136    315     0.43
Dan Uggla         FB     173    406     0.43
Moises Alou       FB      97    235     0.41
Delmon Young      FB     114    291     0.39
Todd Linden       FB      48    124     0.39
Jonny Gomes       FB     107    289     0.37
Eric Hinske       FB      54    149     0.36
Alejandro De Aza  FB      35     97     0.36

The players who have seen the most fastballs are hardly surprising. Names like Bloomquist, Ausmus, Podsednik strike such fear into the hearts of pitchers across the league that pitchers are afraid to throw any off speed pitches to these batters. Or not. These hitters are awful, so pitchers don't waste their good pitches on them because they can get them out with fastballs. If I had included pitchers hitting on the list, they would have filled the top-10. I was a little confused by the inclusion of Thomas and Willits on the list, both of whom are having good seasons, but perhaps advance scouts have seen something in their swings that suggests they can't hit fastballs (or that they hit off speed pitches better than fastballs).

Here's the same chart as above, but for curve balls. Wily Mo Pena has seen the highest frequency of curveballs of any hitter, which makes perfect sense after watching him hit. Pena can't make contact with, let alone hit, off speed pitches, so pitchers have responded by throwing more of them. The rest of the list is characterized mostly by powerful free swingers like Pena who have low walk totals and lots of strikeouts; guys who will chase pitches not necessarily in the strike zone.

Name              Pitch  Count  Total   Freq.
Wily Mo Pena      CB      53    186     0.28
Koyie Hill        CB      36    130     0.28
Felix Pie         CB      21    84      0.25
Jonny Gomes       CB      72    289     0.25
Delmon Young      CB      71    291     0.24
Pedro Feliz       CB     129    562     0.23
Alfonso Soriano   CB     103    453     0.23
Rondell White     CB      38    173     0.22
Aubrey Huff       CB      54    262     0.21
Ben Broussard     CB      67    326     0.21
============================================
Ronnie Belliard   CB      18    258     0.07
Chris Woodward    CB      10    144     0.07
Terrmel Sledge    CB      12    175     0.07
Cody Ross         CB       8    128     0.06
Esteban German    CB      19    308     0.06
Brian Buscher     CB       7    124     0.06
Alex Cora         CB       7    124     0.06
Trot Nixon        CB       6    107     0.06
Luis Rodriguez    CB       3     91     0.03
Tony GwynnJr.     CB       2    118     0.02

It isn't earth shattering that bad hitters will see more fastballs than good hitters, or that Wily Mo Pena-esque hitters will see more off speed pitches than normal. Is this what should be happening though? Intuitively, this makes sense, but it would be nice to see if the numbers back it up. Looking at the Pena's BABIP (or something similar), split by pitch type would be a great way to see which pitch he actually hits well and which ones he misses. Unfortunately, there aren't enough pitches in my database to actually do this for individual hitters now, but it is something to think about for the future.

I'm closing with a chart showing batters who have seen the highest and lowest frequency of sliders. Compared with fastballs and curve balls, there isn't as big a difference between the extreme frequencies and the average frequency for sliders , but its still fun to look at who sees the most sliders.

Name               Pitch   Count   Total   Freq.
Mike Napoli        SL      17       88     0.19
John Buck          SL      47      306     0.15
Jason LaRue        SL      29      191     0.15
Moises Alou        SL      35      235     0.15
Jonny Gomes        SL      43      289     0.15
Nomar Garciaparra  SL      46      314     0.15
Josh Barfield      SL      26      178     0.15
Brian Buscher      SL      18      124     0.15
Curtis Thigpen     SL      17      120     0.14
Toby Hall          SL      28      198     0.14
===============================================
Jason Giambi       SL       4      160     0.03
Frank Catalanotto  SL       9      371     0.02
Felix Pie          SL       2       84     0.02
D'Angelo Jimenez   SL       2       89     0.02
Orlando Palmeiro   SL       2       92     0.02
Jose Cruz          SL       2       93     0.02
David Murphy       SL       3      163     0.02
Tony GwynnJr.      SL       2      118     0.02
Cory Sullivan      SL       3      195     0.02
Brian Schneider    SL       1      165     0.01