THE BOOK--Playing The Percentages In Baseball

There is a clear logic to having a wider distribution for pitch counts rather than lumping it around 100. Some days the pitcher just isn’t hitting his release point or has some other mechanical flaw that causes him to tax his arm. You can probably identify those days by lack of effectiveness/control. I say get the pitcher out of there earlier if he shows himself to be ineffective, and leave him in later if he is having a normal/good day. I’d surmise that 75 pitches on a bad day is probably more damaging than 130 pitches on a better day.

Problem is, managers have 7 man bullpens filled with 1 inning arms and are therefore reluctant to go to the pen before the 3rd or 4th inning even when the starter is clearly struggling.

I’ve always wondered why no one has tried to quantify the impact of warmup pitches and pickoff attempts (and fielding plays I guess) on pitcher fatigue.  Cut out one warmup pitch between each inning and you’ve saved 9 pitches in a complete game.  Keeping a guy like Ricky Henderson close has got to take something out of the pitcher.  Etc.

Have pitchers always taken the same number of warmup pitches between innings, historically?

I also recommend this research I do a long time ago:

http://www.insidethebook.com/ee/index.php/site/comments/do_pitchers_today_have_it_better_because_of_medicine_and_technology/

Which I summarize as:

Of the 96 warrior pitchers born between 1935-1958, they faced an average of 3777 batters at ages 25-28, and followed that up with 2692 batters at ages 29-32 (a 71.3% retention rate).  The pitchers born from 1959-1974 faced an average of 3470 batters at ages 25-28 (that is, babied by 307 batters over those 4 years), and followed that up in their ages 29-32 years with 2648 batters (76.3% retention rate).  Both groups of pitchers, the “overused” legendary pitchers and the “babied technology” pitchers both ended up facing virtually the exact same number of batters at ages 29-32!  Astonishing, isn’t it?
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The short of it all is that, barring war, the average warrior pitcher since Babe Ruth was born has averaged around 2700 batters faced at ages 29-32, regardless of their use at ages 25-28.  Medicine, technology, babying, overusing have not had the impact we would expect.

And then I yap and produce more research at other age levels, and say this:

To finish this off, I took the age 33-36 warriors and see how they performed to the rest of their career.  They also retained about 60% of their BFP, except for the most recent pitchers who retained an enormous 81% (and still going!).  Even their performance has been fabulous.  It’s possible that today’s technology and medicine is helping the older pitchers enormously.

And finally:

Take a pitcher’s entire career.  Select the 64 pitchers with the most BFP for each time period.  Average them.

start end BFP
1895 1902 8,208
1903 1910 8,781
1911 1918 6,648
1919 1926 7,112
1927 1934 7,401
1935 1942 10,199
1943 1950 10,658
1951 1958 9,216
1959 1966 9,955

As you can see, of pitchers born since 1935, there has been no change in batters faced.  Pitchers do have a certain mileage on their arms.  And, the babying of pitchers in their 20s is prolonging their careers in their late 30s.  However, the total mileage is still the same!

Here’s the results for the top 32 pitchers instead of 64:
start end BFP
1895 1902 10,691
1903 1910 11,425
1911 1918 8,509
1919 1926 9,492
1927 1934 9,573
1935 1942 12,687
1943 1950 13,463
1951 1958 11,426
1959 1966 12,313

Fifty years ago, I don’t think we had rotations like we do now.  Managers appeared to do more mixing and matching of starters and relievers.  It’s possible the swing men pitched shorter outings when they started due to work in both the pen and the rotation, which might contribute to the larger spread.  (I’m sorry, I don’t have numbers with me right now, I’m doing this from memory.  I just remember roles for pitchers being much less defined in the 1950s.)

Greg,

I’ve always thought that warm-up pitches introduce a whole new set of variables we don’t know how to account for.  I would speculate that most warm-up pitches are thrown at much less than 100%, maybe 75% effort or so.  My hunch would be that the strain on the arm from a 75% effort pitch is significantly less than a 100% effort pitch, and its quite possible it’s NOT a linear relationship. 

You could probably make similar statements about pick-off throws, fielding plays, and throws in the bullpen before the game (for starters) and during the game (relievers).  And it probably varies from pitcher to pitcher.

Also, do we know that cutting out a warm-up pitch would be better for a pitcher’s health?  Maybe a pitcher’s arm needs X number of pitches at 75% before throwing a pitch at 100% or he’s risking greater injury to his arm?

If we could turn on Pitch F/X for warm-up pitches (and in the bullpen), then we’d have something to work with.

David: using the 128 starts we have of Koufax starting in 1961:

- he averaged 112 pitches per start
- his top 20 in length averaged 151 pitches
- his bottom 20 in length averaged 57 pitches
- the rest of his starts (68.8% of them) were in the 85-138 range, or 112 pitches +/- 26.5

If you were to take off the 16% lengthiest starts for each pitcher and well as the 16% shortest ones, I would bet that for star pitchers, you will get something like this:
- average of 105 pitches
- range of 92-118 (or 105 +/- 13)

That is, the spread in number of pitches will be twice as narrow for the current star pitchers than it was with those of yesteryear.

Note: Koufax averaged 115.5 pitches in his middle 68.8% of starts.

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And for pitchers in the 1990s, I’d bet it was identical to Koufax’s 115.5, as well as the range being +/- 13 pitches, for the 68% of the middle starts.

Greg/BenJ,

My personal (admittedly amateur) experience is that warm up pitches are thrown at roughly 75% and that the effect on the arm is negligible as the relationship between stress and effort, as you guess, is not linear.

I’m guessing a pitcher could throw 4 or 5 times as many pitches at 75% effort as he could at 95-100% effort.

Also, I don’t have the data but I’m guessing that there are only 2 or 3 stressful (95%+ effort) pickoff attempts made in a game. So the effect again is negligible.

This is going in yet another direction, but I wonder if anyone considered the effects of long innings. I would definitely suggest that more stress is inflicted on a pitcher who throws 33 pitches in an inning than a pitcher who throws 3 innings of 11 pitches each. It is beyond me how you could study that though.

If we were talking about weightlifting, a person should be able to do 10 times the repetitions at 75% effort compared to a 100% effort.

I have no idea if those ratios apply to pitching.

Anecdotally, back in the pre-Baseball Reference days I picked up a printed copy of the 1989 American League box scores.  Just like Tango says about the Koufax era, even 20 years ago there was a clear tendency to pull a pitcher after 2 or 3 innings if they were getting knocked around the park.  If it was the ace of your staff you’d even see the pitcher start again in a day or two (Stieb, Morris, Saberhagen, those kinds of guys).  Nowadays, it seems like every starter throws their 90-100 pitches no matter how badly they’re getting beaten up. 

Of course, every bullpen back then seemed to have a long reliever whose specialty was throwing 3 or 4 innings in a blowout or when the starter got knocked out early.  Nobody seems to cultivate those kinds of pitchers anymore.  Where have you gone, Jim Acker?

Over130 means percentage of starts with over 130 pitches thrown.

This is the thread I was thinking about in reference to studes’ post about Bill James and his discovery that starting pitchers in the past had both more longer and more shorter outings.  I knew that wasn’t a novel concept.  I didn’t realize that Keith Woolner was writing about ten years ago.

While revisiting this thread, I found this comment by Brian interesting:

Some days the pitcher just isn’t hitting his release point or has some other mechanical flaw that causes him to tax his arm. You can probably identify those days by lack of effectiveness/control. I say get the pitcher out of there earlier if he shows himself to be ineffective, and leave him in later if he is having a normal/good day.

No one who has looked has been able to identify those bad days (without looking at/judging by the results themselves).  The good starts and bad starts look a lot alike the closer you look at the details of what/how a pitcher is throwing.  The differences, if they are there, are subtle.