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Texas Rangers OF Nelson Cruz, PITCHf/x, and Plate Discipline

In limited action in 2008, Nelson Cruz finally started hitting Major League pitching to the tune of .330/.421/.609. Given the small sample size, people openly questioned whether he had actually turned the corner.

Through Friday, April 17, 2009, Cruz was off to a .282/.356/.718 start, more or less a continuation of his 2008 success. Using PITCHf/x data through the first 10 games of 2009 and some stats from Nelson Cruz's FanGraphs profile, here's a little plate discipline analysis to see if it supports his impressive start.

The black boxes in these charts are approximations of the actual strike zone. Based on average PITCHf/x data for Cruz's at-bats, the bottom of Cruz's strike zone is about 1.6 feet from the ground, and the top of his strike zone is about 3.4 feet from the ground. The left and right edges of the zone are approximated at 1 foot to either side of the plate based on half the plate's width (8.5 inches) plus some wiggle room for pitches that scrape the black (3.5 inches). (NOTE: All location graphs are from the catcher's perspective.)

The first chart shows us what Cruz has been swinging at by location and by pitch type.

Based on this chart, Cruz has mostly been swinging at strikes. According to his O-Swing% at FanGraphs, only 20.2% of these pitches are outside of the strike zone. That is the lowest of his career. Since his 2006 Rangers debut, his O-Swing% has dropped every season - 29.4% in 2006, 26.5% in 2007, and 23.1% in 2008.

Notice that Cruz hasn't swung at many pitches near the bottom or near the outside edge of the zone. This has helped Cruz lay off of breaking pitches away. Through 10 games, Cruz had not swung at a single pitch off the outside edge of the plate.

The second chart shows us what Cruz hasn't been swinging at by location and by pitch type.

This chart fills in the obvious holes from his swings chart. There are a lot of pitches in the zone low and away that Cruz has not swung at. According to his Z-Swing%, Cruz has swung at 78.5% of pitches in the zone. Based on that stat, the chart doesn't exactly match up. It appears that he's been taking pitches in the zone more often than 21.5% of the time. This could be the result of the PITCHf/x strike zone not matching up with the zone being called by the umpires.

Without getting in too terribly deep, here's a quick look at the righty-lefty split broken down by location and pitch result. The small sample against lefties in the first 10 games doesn't give us much to look at, but the righties scatter plot is interesting.

The PITCHf/x strike zones for Cruz appears to be pretty accurate. Keep in mind that some of the strikes outside of the zone were swung at.

Let's look at Cruz's Z-Swing% again. My rough count based on my unofficial strike zone suggests a 61:23 ratio or a 72.6% Z-Swing%, which would still be a career high for him. From 2006 through 2008, Cruz's Z-Swing was very steadily between 70% and 71%.

This year, he's swinging at strikes more often, but he's also swinging at fewer pitches overall - 46.8% in 2009 versus 50.8% in 2006, 49.6% in 2007, and 47.1% in 2008.

April 19, 2009 Update: Cruz has reached base safely in all 12 games this season on 13 hits and 7 walks against only 10 strike outs. He is now hitting .289/.377/.667.

The numbers and charts say he's being more selective than ever. This can only be good news for Cruz, the Texas Rangers, and their fans. I believe that Nelson Cruz has finally arrived.

Some other observations:

  • Very few pitches have been thrown low and in to Cruz. I wonder if his AAA scouting report says to stay away from that quadrant.
  • Righties stand a good chance of getting Cruz to put the ball in play by throwing him up and in.
  • Cruz's first-pitch strike percentages by year: 62.3% in 2006, 63.4% in 2007, 52.6% in 2008, 51.0% in 2009. It's a small sample size and might not mean anything anyway, but it is interesting.
  • One step further, Cruz is seeing fewer strikes than ever: 52.5% in 2006, 52.4% in 2007, 50.2% in 2008, and 45.7% in 2009. Combined with the stat above, I'm pretty sure this means something.
  • One concern: what happens when opposing pitchers start hammering that outside corner?

Reader Comments (8)

On your concern: If a pitcher is good enough to consistently hammer the outside corner they will get him out. And almost everyone else, too.

April 20, 2009 at 1:23 PM | Unregistered CommenterNCRF

That's obviously true, but I'm not talking about "a pitcher." Take another look at that outside corner in the graphs.

According to my unofficial strike zone, the frequency of pitches he sees on that corner is very low. Pitchers are either missing off the plate where Cruz has been laying off the pitch, or they are catching way more than just the corner of the plate.

April 20, 2009 at 1:28 PM | Registered CommenterTrip Somers

One issue is that pitches thrown at the low outside corner are less likely to be called strikes by the umpire, even if it is actually a strike by the rulebook. On the "take" chart, you can see that half of the pitches he has taken in the strike zone on the outside corner was actually called a ball.

The reciprocal is true - one problem with pitchers like Matt Harrison is that they aim for the lower edge of the plate, and the probability of getting strikes called there is naturally lower even if the pitch is in the strike zone, so it looks like they have worse control than they actually do

April 20, 2009 at 4:41 PM | Unregistered CommenterT.E. LeGraf

You can argue that pitches on the outside corner are less likely to be accurate since umpires typically stand over the inside corner, but I don't think you can argue that pitches on the outside corner are less likely to be strikes.

Based on Cruz's charts, your statements hold up, but Tom Glavine would argue with you on both of your points. His career, particularly the last 10 years of it, was built on low and away, and he was never a guy whose control was questioned by scouts, players, or umpires.

April 20, 2009 at 5:13 PM | Registered CommenterTrip Somers

No, it's not an argument, just a trend in general observed from the pitching data collected. Someone over at THT did a study on this a couple of year ago:

Essentially, it says umpires in general has a trend of widening the strike zone on both sides of the plate, but shrinking it toward the bottom for right handed hitters, and widening the outside part of the plate while shrinking top and bottom for left handed hitters.

April 20, 2009 at 5:54 PM | Unregistered CommenterT.E. LeGraf

That comment is the opposite of what you said before. According to the study you cited as well as what you wrote in your comment, balls on the outside corner are *more likely* to be called strikes.

Please don't start an argument with me about what is and isn't an argument, especially in my blog comments.

April 20, 2009 at 10:59 PM | Registered CommenterTrip Somers

Hilarious. Just as I finish reading this article, Nelly hits a shot off of Halladay

April 21, 2009 at 6:29 PM | Unregistered CommenterJason Rutherford

I apologize if the last comment sounded rude, that was not my intention. However, I do not believe there is a contradiction in what I said. I am specifically talking about the "low outside" corner - not the entire outside portion of the plate. Therefore, I am not trying to refute your point, only to offer a slight caveat to it. I said in the first comment that pitches on the low outside corner are less likely to be called a strike, and in the second comment, I pointed to the study where this is supported. It is true that on average, the umpire's strike zone is expanded so that the effective strike zone is wider, but not at the bottom of the strike zone.

The point I was trying to make was that in the past, Cruz had problems laying off breaking pitches thrown to the low outside corner. If he now takes just goes ahead and take those pitches, he does himself a huge favor since even if those pitches are strikes - they are less likely to be called as such.

April 23, 2009 at 11:20 AM | Unregistered CommenterT.E. LeGraf

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