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Rivera closing the Phils out

On Wednesday, Moshe pointed us to an article on Rational Pastime called “Mariano Watch: April” which detailed in glorious fashion the interesting phenomenon surrounding Mariano’s cutter.  The piece first began by showing that Mariano’s fastball velocity is down when compared to this time last year.  As you can see in the chart below (courtesy of Rational Pastime), he’s ranging between 0.2 and 0.6 mph slower on the cutter so far.

Average CT FB Velo

Fangraphs confirms that his velocity has been on a downward track since 2007, but this isn’t really news to Yankees fans.  J-Doug wonders, as have many analysts, why Rivera’s effectiveness hasn’t decreased along with his velocity.  He plots the average break on Rivera’s cutter, using all kinds of fancy math, and notes that the cutter is breaking a full inch more in 2010 than it is in 2009.  To wit:

Average CT FB Break

So why I am bringing this up again?  Well, a few months ago Moshe tweeted that a source, which was me, passed along some insider information about Rivera and his approach to his cutter.  Rivera wasn’t concerned about the drop in velocity, and the reason was the he had noticed that he was able to generate more break on the cutter when it was thrown slower.  Now, from a physics perspective, I’m not exactly sure why it works like this.  Is it simply a matter of it taking slightly longer to get to the plate, and having a longer time to “spin”? Or does the velocity affect the break of the cutter in a different, more fundamental way? Does throwing it 3-4 mph faster make it straighter?  Can anyone explain Mariano Rivera and his ability to defy aging?

When I originally heard this information about his cutter, I thought it was cool and interesting but maybe just a tad bit apocryphal.  It sounded like the kind of story you hear a hundred times over in Spring Training: Player X lost 20 pounds, Player Y learned a changeup (ahem, Hughes), Player Z got LASIK.  Far be it from me to doubt the great Mariano Rivera, but I wasn’t absolutely certain that the Pitch F(x) data would back up his claims.  But Rivera was right.

There is, quite obviously, an uneasy tension between the more stats-oriented fanbase and the “scouting” fanbase, if I could use two very general and inaccurate terms.  I enjoy participating in the mocking of the stories like the ones I listed above.  I’m skeptical of any story written about how a player got a new workout routine and seems poised for a breakout year, unless it’s based on firm statistical analysis.  There’s a good reason for this: most of the stories turn out to be nothing more than filler that helps pass away the interminable days of PFP and intersquad matchups in March.  But beyond that, and I’m certain that I’m not the first to suggest this, maybe there is room for a little “mystery” when it comes to approaching this game.  In this case, the narrative of Mariano’s cutter preceded my ability to verify or validate it, but it was true nevertheless.  I like this.  And I like that people smarter than me are able to prove Rivera, who was just going on his sight and his feel, correct.  There’s a lot of tension, even dislike, between the camps of stats vs. scouting, new vs. old, proof vs. feel, etc.  A lot of times there doesn’t seem to be too much respect or open-mindedness in the conversation.  In this case, I appreciate that the two don’t need to be mutually exclusive.  Mystery and hard science can live next to each other, one validating the other.  And who better to embody it, to stand in the middle, than the great Mariano Rivera?

9 Responses to “Skepticism and Mariano’s Magic Cutter”

  1. Rivera gave up a grand slam?

    I take it all back.  (Quote)

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  2. great post- i’m one of those guys that are “in the middle” re stathead vs seeing with my own eyes. and not to worry- you didn’t jinx Mariano today  (Quote)

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  3. “Now, from a physics perspective, I’m not exactly sure why it works like this. Is it simply a matter of it taking slightly longer to get to the plate, and having a longer time to “spin”? Or does the velocity affect the break of the cutter in a different, more fundamental way? Does throwing it 3-4 mph faster make it straighter?”

    I am a pitcher and has been for the last 8 years. The reason his cutter cuts more when thrown slower is simply because the arm movement required for it to cut is more pronounced. It’s the same for all pitches. The more the arm movement to execute a certain pitch (except for the 4-seamer) is pronounced, the slower you’ll throw. That’s why you’ll rarely see a 85-mph curveball but will see a slider with that velocity although both have the same spin action. I don’t think it has anything to do with physics.  (Quote)

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    Stephen R. Reply:

    Can you explain what you mean by arm movement? Are you talking about arm angle, arm speed, or the action his fingers create on the ball?  (Quote)

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    John Reply:

    Sorry. “Arm movement” is not very clear. By arm movement I mean the action that the arm (especially the wrist and the fingers) has to do in order to throw a certain pitch. For instance, in order to create the downspin of a curveball, the pitcher has to roll his palm and fingers over the top of the ball when releasing it. What influence the cut of the cutter is generally the arm slot angle and the pressure points of certain fingers. The more these factors are increased (greater twist of the wrist for the curveball, greater pressure on the fingers for the cutter, etc.), slower will be the pitch. Hope this helps.  (Quote)

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    Stephen R. Reply:

    Thanks, that makes sense. Hard to say what it is, because Rivera’s comments make it seem like its the decrease in the velocity creating the additional movement, not a change in arm angle or finger pressure on the ball. It would be interesting to take a look at his angle from last yr. to this yr. to see if anything has changed.  (Quote)

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  4. Mariano had a long period of no pitching and might need a few more appearances, no biggie but it probably doesn’t happen if Cervelli is back there.The more we see Cervelli back there, te worse Jorgie looks as a receiver.
    Has Jorge EVER stood up and asked for a High fastball.
    Got Robertson in trouble too imo, because he was afraid to give up a stolen base and wouldn’t call a curve.  (Quote)

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    Moshe Mandel Reply:

    Oh, give it up. This is just a silly comment. Posada also called the whole game, when Mitre pitched well. And he called the playoffs last year. And in 2000. And part of 1999. And 1998. Jorge stands up for a high fastball all the time.  (Quote)

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