Carlos Zambrano and the cut fastball

Every once in a while a pitcher actually talks in detail about his stuff. Thursday morning, beat writer Carrie Muskat shared this juicy detail via her Twitter account:

Not only has #cubs Carlos Zambrano lost 15 pounds, but he also is dropping his cutter. Says that’s the one pitch he couldn’t control well

Well, that just about knocked me over. My good friends at Another Cubs Blog suggested, via Twitter, that Zambrano may be going back to his old (pre-2006) ways—relying more heavily on his sinking fastball and putting a little extra on his slider more often. Which made me feel good, since I had just speculated along those lines in my own tweet (seriously, Twitter is great for baseball fans, if you haven’t noticed).

Now that I’ve caught you up on the latest from the world of social media, let’s talk about Zambrano’s stuff. I’ll explain why this news was a surprise to me.

Zambrano’s seven pitches

Seven pitches, that’s a lot. A fastball (four-seam), sinker (two-seam), splitter, slider, cutter and a few slow overhand curveballs and even a straight change here or there. Take away one, and discount the rare birds, Zambrano is already calling himself a four-pitch pitcher. More from Muskat, this time on her blog:

The 28-year-old pitcher says his repertoire will now include a sinker, slider, split and “high fastball.”

That fourth pitch is almost certainly a four-seam fastball, which Zambrano likes to get up in, and out of, the zone. And, yes, he’s still just 28, but 2010 will be his age 29 season.

Going back to 2007, here are the seven pitches thrown by Zambrano, from most to least thrown.

Pitch MPH Number
Sinker 91.8 2116
Fastball 92.2 1858
Cutter 91.1 1352
Splitter 85.1 850
Slider 82.4 755
Curveball 67.9 39
Change-up 82.5 16

Dropping the cutter is no small deal. I’ve enjoyed his ability to work a fastball three ways, but I guess I can still cling to his sinker.

Using some spin deflection charts (deviation from path of a ball only under the influence of gravity, catcher’s view, in inches) lets me illustrate those pitches. It’s also Olympics season, so I’ll use rings instead of colored dots when appropriate.

First, the average pitch (2007-2009) for Zambrano. The color key is used again in the other charts, so make a mental note. The average pitch speed is shown within the bubble.


Now the rings of Zambrano for 2009 only.


Yes, that’s a lot of overlap. Let’s fill those in with the actual data points to really blur the lines.


Before you conclude that the cutter is not correctly split from the fastball, these pitches are classified game-by-game (sometimes by inning or at-bat). Here are those same rings (unfilled and filled) for Zambrano’s Aug. 25, 2009, start.


But, as the data points show, there are places on the margins that could be adjusted.


What’s not shown is the 2 mph difference in speed as you cross the border from fastball to cutter. Still small enough to be a data error and/or reclassified.

Run values and this Cub fan’s paranoia

Now for the surprise, or at least my surprise at the news. Based on my pitch classifications and my calculations of linear weights and pitch-by-pitch run values, Zambrano’s cutter is arguably his best pitch. It’s clearly the best of his fastballs. The sinking and “high” versions are easily outperformed by the cut fastball.

rv100 is based on the actual outcome (ball, strike, single, out, etc.) while rv100E uses balls and strikes along with batted-ball type—as in line drive, fly ball, ground ball and pop-up (as designated by MLBAM’s Gameday stringers). Each batted-ball type is given a value based on the league average for that type—a weighted average of run values for each outcome (a little single, a little out, a little home run, etc.). It overcontrols for variance in parks and fielders, but offers a comparison point (or regression target) for rv100. For both metrics, negative values indicate runs saved compared to an average pitch.

2007 2008 2009 Total
Pitch rv100 rv100E rv100 rv100E rv100 rv100E rv100 rv100E
Sinker 0.51 0.06 -0.66 -0.46 -0.36 0.03 -0.36 -0.20
Fastball -0.34 0.30 -0.19 0.73 0.14 -0.09 -0.08 0.27
Cutter -1.21 -0.91 -1.38 -0.75 -1.14 -0.70 -1.26 -0.78
Splitter -2.87 -0.11 -0.58 0.61 -0.99 -0.07 -1.19 0.17
Slider -1.93 -0.71 -0.24 -0.75 -0.44 -0.77 -0.65 -0.75

Unless throwing a cutter is somehow too demanding physically—I do not know if the pitch would bother his shoulder or forearm, which is also a pain point for Zambrano—I really don’t understand why he’s not throwing it anymore. He did offer a clue about control, which provides the direction for the next step in this study. Meanwhile, someone who knows more about pitching injuries and bio-mechanics can opine on the purely speculative theory on arm strain. Or maybe a beat writer can ask a few questions.

References & Resources
PITCHf/x data from MLBAM and Sportvision. Pitch classifications by the author.

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Peter Jensen
12 years ago

Wonderful research Harry.  I find it interesting that Zambrano’s RV100 on the cutter is always lower (better) than his RV100E.  If his problem with it is control you would think it would be the other way around, that he would be being hit better than the league average on “mistake” pitches.

Harry Pavlidis
12 years ago

Peter – Thank you.

I’m perplexed, hence the speculation on health issues. It looks to me like Z’s cutter, as you’ve alluded to, yields poor contact relative to the “expected” outcomes. As in, those liners are softer, the fly balls higher and/or weaker (his pop up rate on the cutter is .16).

I touch on the rv100/rv100E relationship a little bit in the MPS Cardinals annual (“Twin Peaks” on Carp. and Wain.) and it needs deeper study. The gaps between rv100 and rv100E are “luck”, “defense” and “contact quality” related. I just don’t know how to tease those apart. Yet.

12 years ago

As a Cub fan regarding Zambrano. I wouldn’t be as concerned with a missing cutter, as I would be the few missing marbles!

Peter Jensen
12 years ago

I just don’t know how to tease those apart. Yet.

I haven’t thought about this as much as you have, but off the top of my head I would think that if it were luck you would not see the year to year consistency that Zambrano’s 100 vs. 100E differential shows, and that if it were defense other pitchers on the same team would show similar differentials.  Especially pitchers who had similar characteristics of Handedness and GB/FB ratios.

I would like to see a third category added to rv100 and rv100E.  That would be rv100G where the value of the pitch is given the average value of a strike or a ball without the context of the count and hit balls are given the hit ball value as in rv100E.  The “G” stands for generic.  rv100G would not include the bias of having certain pitch types used in certain counts.  If Zambrano was worried about his control of his cutter he may have avoided using it in counts where a ball would have resulted in a walk and used it more often than average in counts where it could result in a strikeout.

12 years ago

Zambrano’s BB/9 is putrid against LHH hitters during his career, 5.21 opposed to 3.21 against righties. What Peter said about having a balls and strike run value type might be useful.

For the Draysbay annual, I used the run values for just balls and strikes (based on the count) and called it prv100 (p for plate) similar to what Peter is talking about. This was to take hits out of the rv100 metric. Although I am not sure exactly what it’s use was.

12 years ago

Cutter’s and arm strain? 

The general understanding is that pitches thrown with a supinated (turning a doorknob counter clockwise for a RH) arm action are generally more stressful on the elbow than a pronated pitch because the stress of accelerating and decelerating the arm is being focused mainly on the ligaments instead of allowing the arm to bend naturally and absorb some of the force.  Mariano Rivera has pristine mechanics, and despite this and limited innings as a reliever he still has a history of elbow issues due to how often he throws the cutter.

However, if a pitcher were to pronate their arm immediately after release of a supinated pitch, they might be able to reduce the stress significantly.  A good example of such an act that I know of would be Roger Clemens throwing his slider.

Nick Steiner
12 years ago

This is great work Harry.  Very simple and to the point, with lots of info and a nice hard conclusion. 

Regarding the gap between rv100 and rv100E, I think some of that is going to be due to the very short amount of time he takes between pitches.  Although Mike Fast found basically zero correlation between time between pitches and BABIP:

I think there is still something to the theory, and Zambrano is one of the quickest pitchers in baseball.

12 years ago

From personal experience pitching through college and semi-pro ball, I would say that the cutter is undoubtedly more stressful on your elbow and shoulder than any other type of fastball. While not as stressful on the elbow as the slider, it is close, and I actually found that the motion for the cutter is more stressful on the shoulder than the slider. If Zambrano is having lingering problems with his arm, it very well could have something to do with the cutter.

Rick Sowers
12 years ago

Iamcomparing this to Hamels of the Phille’s.Some add and have to many pitches. The cutter seems to be a required pitch.Without it he may loss the upperhand.

  Rick a Phillies Fan