Makin' a Filter
Jamie Moyer and Josh Beckett both throw fastballs, but while Moyer's tops out around 85 MPH, Beckett's travels 10 MPH faster. Looking at each pitcher separately, it's easy to classify their fastball, but the only thing the two fastballs have in common with each other is that they are the fastest pitch each pitcher throws. In order to expand my examination of when pitchers throw certain pitches, I want to classify every pitch that has been tracked by the pitch f/x system as either a fastball or off-speed pitch. In order to effectively differentiate between the two groups of pitches, each pitcher has tobe compared to himself and not an outside standard that would classify Moyer's 85 MPH fastball as an off-speed pitch.
In each appearance by a pitcher, I found the average speed of his pitches as they crossed the plate, and then divided the velocity of each pitch in that appearance by the average, which gave me a value for each pitch, standardized for that day. I then classified each pitch as a fastball or off-speed, using only that standard value. Obviously this isn't a perfect method for classifying pitches, and there is some level of inaccuracy with the labels, but it's simple, relatively accurate for fastballs vs. off-speed pitches, and I think it's a good start in automating the classification process.
Testing the method on individual pitchers, the results generally agreed with a visual inspection of their pitch chart, but the algorithm I used to classify pitches had problems with certain types of off-speed pitches. To fix the problems I used a cut-off point of the standard value to separate fastballs from everything else. Generally speaking, a pitch that was faster than the average speed was usually a fastball and anything slower was off-speed. This was the case for every type of pitcher I examined, which will be important.
Some pitches are going to be improperly classified with this method as well, but the problem is smaller compared to using the algorithm and because of the similarity between different types of pitchers, this method worked better than the algorithm when classifying pitches for multiple pitchers. Here's a pitch chart from Roy Halladay to give a sense of where the distinction is being made between pitches.
One thing to keep in mind, and it's shown clearly in Halladay's graph, is that I didn't make any attempt to separate 2-seam and 4-seam fastballs for pitchers that throw both pitches, which will slightly skew the results for those pitchers.
Once I was automatically classifying individual pitchers, I went back and classified every pitch in my database as either a fastball or an off-speed pitch. Before I looked at when pitches were thrown though, I needed to establish some baselines. Of all the pitches in my database, 62% have been fastballs. Some basic splits are in the table below.
Split Fastball% Total Pitches Overall 62% 122072 RHP/RHH 63% 46849 RHP/LHH 61% 43197 LHP/RHH 61% 23415 LHP/LHH 63% 8611
It seems that pitchers throw more fastballs to same-side hitters, but overall 62% looks pretty good as an average. Here's a list of the 10 pitchers who throw the highest and lowest percentage of fastballs (min 100 pitches).
Name FB% Total Pitches Scot Shields 75% 531 Todd Jones 75% 116 Darren Oliver 75% 357 Joakim Soria 75% 206 Alan Embree 73% 380 R. Betancourt 73% 173 Jay Marshall 73% 319 Mike Timlin 73% 146 Aaron Sele 72% 127 Macay McBride 72% 263 ------------------------------ Cole Hamels 48% 341 Ian Snell 47% 285 Akinori Otsuka 46% 293 Tom Glavine 46% 324 Matt Wise 46% 121 C. Villanueva 45% 508 Royce Ring 44% 248 Kiko Calero 44% 314 Justin Speier 42% 363 Jamie Walker 37% 151
This list is pretty interesting and the full list it came from might be even more interesting. First of all, Jamie Walker throws a ridiculously small percentage of fastballs compared to the league average. 37% is more than 3 standard deviations from the mean, so he must have reasonably good off-speed pitches to rely on them so extensively. Comparing pitchers to each other gave me insight into some differences in pitch selection I was unaware of. I knew Hamels and Glavine relied heavily on pitches other than their fastballs, but I had no idea they threw their fastballs less than half the time. Similarly, I was surprised at how frequently the leaders threw their fastballs. Joel Zumaya missed the pitch limit cut-off, but he threw his fastball 84% of the time. Hitters essentially knew his fastball was coming, but there still wasn't much they could do with it. One other tidbit from this chart is regarding Beckett. He was subject to criticism last season that he was relying on his fastball too much. This season he has thrown it 65% of the time this season, which is above average, but not in the category of 'over-reliance'.
In a previous article, I examined the pitch selection of Jake Peavy and Dan Haren, based on the Leverage Index of the situation. I didn't have any baselines to compare their averages too, but now I do. Instead of using LI to separate situations, I took a suggestion from a comment by Tangotiger and created three groups of situations based on the run value of a strikeout vs. regular out. Using the win value of a strikeout vs. regular out would probably be a better distinction, but that's for another article. A strikeout is much more valuable than a regular out primarily when there are runners on third base and less than two outs, while the value of a regular out is higher than a strikeout if there is a runner on first or first and second, with one or no outs. The chart below shows the fastball percentages for each situation, split by the pitcher/batter matchup.
Split High K Low K Everything Else Overall 60% 64% 62% RHP/RHH 62% 65% 63% RHP/LHH 60% 64% 61% LHP/RHH 58% 63% 61% LHP/LHH 63% 64% 62%
In every case, the percentage of fastballs thrown is lower when the pitcher needs a strikeout, which is what we expected going in (and saw in the case of Peavy and Haren). The differences between situations aren't severe, but in the 'overall' case especially, the sample size is large enough that the differences are real.
Below is a table showing the pitchers who have thrown the highest and lowest percentage of fastballs when they need a strikeout (min 20 pitches). It is a little misleading to just compare the percentage of fastballs a pitcher throws when he needs a strikeout to the league average and say anything less than the league average (more breaking balls) is good while anything higher is bad. A pitcher should throw whatever pitch he has that can get the most swings-and-misses in a high K situation, and for some pitchers, their best swing-and-miss pitch happens to be their fastball. Pitchers rely on their fastballs generally, but certain pitchers should and do use it even more in situations where they need a strikeout.
Name FB% Total Pitches Carlos Silva 88% 25 Matt Belisle 87% 23 Greg Maddux 84% 43 Chris Sampson 81% 21 Vicente Padilla 80% 111 Adam Eaton 79% 29 Manny Delcarmen 79% 33 Odalis Perez 77% 31 Scot Shields 77% 31 Jay Marshall 76% 34 ----------------------------------- Rudy Seanez 39% 28 Javier Lopez 39% 41 Vinnie Chulk 38% 21 Matt Cain 38% 29 Will Ohman 36% 22 C. Villanueva 36% 22 Mike MacDougal 35% 20 Kelvim Escobar 34% 62 Scott Baker 32% 25 Mike Thompson 32% 22
Manny Delcarmen is one of the pitchers who relies more on his fastball when he needs a strikeout and we can see whether he should be or not. Delcarmen gets a swinging strike 13% of the time he throws his fastball (in any situation), while he gets a swinging strike only 10% of the time with his off-speed pitches. If those ratios are real, and not the product of a small sample size so far, Delcarmen appears to be justified relying on his fastball more when he needs a strikeout. The downside to this is if hitters know a fastball is coming nearly 80% of the time with a runner on third and less than two outs, it would seem to lose some of it's swing-and-miss capabilities...unless it is such a good fastball that hitters can't hit it even when they know it's coming, in which case a pitcher should use it more heavily when he needs a strikeout. There should be some point where that circular loop ends and an equilibrium is reached between the amount a pitch is thrown and it's ability to cause swings-and-misses.
I've covered some of the flaws in the methodology I used to separate pitches, but overall I was quite happy with the results. When I compared the overall fastball percentages for individual pitchers to Inside Edge on ESPN and my own individual pitcher graphs, the percentages were close in all three cases. The next step in this type of analysis is to separate out the different off-speed pitches that I lumped together, which adds another layer of information about pitchers and pitch selection. A changeup and curveball are two very different pitches and could be used for very different purposes by a pitcher.
I'm going to close with one last table, this one showing the fastball percentage on extreme pitcher's counts (0&2 and 1&2) and extreme hitter's counts (3&0, 3&1).
Count Fastball% Total Pitches 3&0 and 3&1 83% 4340 0&2 and 1&2 54% 18091
I should have separated the 3 ball counts by the cost of a walk, but it seems amazing that pitchers are so afraid of walking a hitter in those counts that they become Zumaya-esque in terms of pitch selection, but without the amazing fastball to back it up. In a count that already favors the hitter, hitters see almost all fastballs, which is one big reason why hitters have a .630 SLG in 3&0 and 3&1 counts this year.