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Robert Arthur 

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10-29

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2

Moonshot: Do the Giants Beat the Heat?
by
Robert Arthur

10-22

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8

Moonshot: The Royals, the Strike Zone, and an October Surprise
by
Robert Arthur

10-15

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18

Moonshot: The Victims of a Bad Strike Zone
by
Robert Arthur

10-08

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7

Moonshot: Fastballs and the Collapsing A's, Part 2
by
Robert Arthur

10-02

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23

Moonshot: Fastballs and the Collapsing A's
by
Robert Arthur

09-19

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6

Moonshot: Detecting the Best Medicine
by
Robert Arthur

09-09

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0

BP Unfiltered: BP At Fox Sports: The Impact of the Evolving Strike Zone
by
Robert Arthur

09-09

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8

Moonshot: The Year In Zone Distance, and Next Year in Breakout Candidates
by
Robert Arthur

09-03

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18

Moonshot: Time vs. Pace
by
Robert Arthur

08-28

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12

Moonshot: On Regressing Defense
by
Robert Arthur

08-20

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38

Moonshot: The Analytic Value of the Crack of the Bat
by
Robert Arthur

08-12

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2

BP Unfiltered: Sveum's Unheard Guide to Fixing Royals' Offense
by
Robert Arthur

08-06

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10

Moonshot: Troy Tulowitzki and the Brittle Bones Hypotheses
by
Robert Arthur

07-30

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25

Moonshot: Separating the Phenoms Who'll Make It From Those Who Won't
by
Robert Arthur

07-22

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11

Moonshot: Accounting for Count
by
Robert Arthur

07-18

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3

BP Unfiltered: BP at Fox Sports: Anthony Rizzo and the Making of An All-Star
by
Robert Arthur

07-16

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5

Moonshot: The Matter of the Heart
by
Robert Arthur

07-08

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1

Moonshot: Survival of the Fittest: Position Players
by
Robert Arthur

07-01

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1

Moonshot: Survival of the Fittest: Pitchers
by
Robert Arthur

06-24

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21

Moonshot: Dale Sveum and the Royals Remedy
by
Robert Arthur

06-17

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5

Moonshot: Striking Distance
by
Robert Arthur

06-10

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4

Moonshot: Learning from Yasiel Puig's First Year
by
Robert Arthur

06-03

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5

Moonshot: What Makes Position Players Injury Prone?
by
Robert Arthur

05-21

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6

Moonshot: PITCHf/x and Batter Breakdowns
by
Robert Arthur

05-12

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10

Moonshot: Predicting Batter Breakouts with PITCHf/x
by
Robert Arthur

05-05

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7

Moonshot: The Winding Path of Albert Pujols, Via PITCHf/x
by
Robert Arthur

04-28

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19

Moonshot: How Quickly Do Team Results Stabilize?
by
Robert Arthur

04-23

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6

Moonshot: What PITCHf/x Can Tell Us About Batters
by
Robert Arthur

04-14

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8

Moonshot: Does April Velocity Last?
by
Robert Arthur

04-08

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10

Moonshot: Miguel Cabrera and the Bearable Heaviness of Being
by
Robert Arthur

04-01

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7

Moonshot: Cracking the Location Code
by
Robert Arthur

03-25

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5

Moonshot: Attrition Over Time
by
Robert Arthur

03-14

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16

Attrition By Position
by
Robert Arthur

03-12

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8

The Art and Science of Sequencing
by
Robert Arthur

02-06

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14

Baseball ProGUESTus: Entropy and the Eephus
by
Robert Arthur

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August 6, 2014 11:09 pm

Moonshot: Troy Tulowitzki and the Brittle Bones Hypotheses

10

Robert Arthur

Are injury prone players actually prone to injuries?

In a twist of stunning unpredictability, Troy Tulowitzki is injured. Like the year before, and the year before that, Tulo is spending some time on the 15-day disabled list, after missing a handful of games for sprains and strains earlier in the season. Troy’s annual trip breaks up what was easily (on a rate basis) the best season of his career.

A glance at Tulowitzki’s injury history reveals a voluminous catalog of the many ways baseball players can be hurt. This year, Tulowitzki suffered a hip flexor strain. Last year, Tulowitzki had broken ribs. The year before, a torn muscle which necessitated surgery. Other injuries on his record include maladies in his foot, ankle, and hand.

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And trying to figure out whether we can do it quickly.

Predicting rookie players’ performances is one of the most difficult tasks for any projection system. By definition, they lack the extensive body of work necessary to analyze their performance. While it’s tempting to foresee a Hall of Fame career in the demeanor of one at-bat, statistics (as well as common sense) caution against it. No matter how locked in or lost a player looks in the sample of a few games, his true skill cannot be inferred from such meager experience.

The ultimate cautionary tale here is Mike Trout, whose first year (2011) MLB stats go like this: .220/.281/.390, in 135 plate appearances. Such a line is not the stuff from which legends are made, and had a lesser prospect posted it, there might have been rumblings of doubt in the media. Trout was decidedly not a lesser prospect, and his raw combination of discipline and athleticism had every scout and fan salivating despite the poor batting average. Even so, it’s still possible to find a few sentences in the press reports of that time which noted his difficulties:

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July 22, 2014 6:00 am

Moonshot: Accounting for Count

11

Robert Arthur

Looking at behavior by ball-strike situation reveals one of the ways hitters change most drastically from year to year.

The count controls all aspects of the batter-pitcher battle. From pitch type to location to swing tendencies all the way to the batted-ball outcome of a thrown pitch, nothing escapes the influence of the count. Like many statistics in baseball, credit for the count itself is difficult to parse. If a pitcher falls behind in a count, it could be because he is having trouble locating his pitches, or it could be because he is afraid to challenge the hitter in the zone. Conversely, a hitter’s ability to drive into favorable counts could be because of a good eye or a good approach or the ability to inspire a fear of the zone in the opposing pitcher.

I came to the conclusion recently that, because of the pervasive influence of the count, certain plate discipline statistics must be taken with a grain of salt (or an extra grain, if you were already taking them with the pre-recommended grain). I came to this realization because I was examining a certain hitter’s swing rate, and noticed that while his overall swing rate differed little between years, his swing rate on particular counts had changed quite substantially—that is to say, his approach, as a function of the count, had changed. However, when the positive and negative changes in swing rates were averaged, the overall difference in swing rate became muted, concealing the difference in approach.

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How Anthony Rizzo Became an All-Star

Despite Anthony Rizzo’s ignominious strikeout in the All-Star game, a look at BP’s leaderboards reveals he’s having a monster year—good for the 11th highest BWARP in MLB. So while Rizzo’s performance this year has been nothing short of exceptional, his breakout came a year too late, as I write in this week’s BP on Fox article.

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July 16, 2014 6:00 am

Moonshot: The Matter of the Heart

5

Robert Arthur

Is it safe to treat all pitches down the middle as more or less the same?

On Friday, Bill Petti wrote an interesting article at the Hardball Times on predicting the success of hitters based on the way pitchers attack them. If that sounds familiar to you, dear reader, it might be because it’s a topic about which I have written at great length in the recent past. To recap, I found that changes in the distance at which a pitcher threw to a batter could predict whether a batter was primed for a breakout or, conversely, likely to underperform his projection.

Petti found very different results in his study, however. Using a metric of his own invention called Heart%, Bill found that there was no trace of predictive power in changes in Heart% both within and across years, replicating the general approach which I had used. Let me say at the outset that I have the greatest respect for Bill and his work, especially with regards to the zone partitioning scheme which he and Jeff Zimmerman invented (which resulted in the useful statistic Edge%). So I do not mean the remainder of this post to denigrate in any way the work Bill did in this or other studies.

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July 8, 2014 6:00 am

Moonshot: Survival of the Fittest: Position Players

1

Robert Arthur

How can we tell which hitters will have long careers?

In last week’s article, I extended my approach of survival modelling to examine what the early career success of a pitcher can tell us about his long-term survival in MLB. Despite the inherent randomness of the pitching profession in the age of Tommy John surgery, I discovered that by far the best predictor of a long career was the age at which a player debuted in MLB. Besides debut age, the abilities to rack up strikeouts and avoid walks meant the most for a pitcher’s long-term career outlook.

I turn the same method now to position players. Position players have different risks from pitchers, and a different set of career arcs. Position players are less likely to be hur, and more able to continue their career in the face of injury by moving down the defensive spectrum. What’s more, whereas a pitcher contributes the vast majority of his value from his pitching, a position player might be great in several different ways: by hitting, by fielding, or even (to a lesser extent) by baserunning.

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July 1, 2014 6:00 am

Moonshot: Survival of the Fittest: Pitchers

1

Robert Arthur

How do we know which hurlers will have long careers?

In the recent past, we’ve seen the rise of a generation of young and highly talented pitchers. From Corey Kluber to Chris Sale, from international acquisitions like Masahiro Tanaka to the sadly injured Jose Fernandez, young hurlers occupy an increasing share of the game’s best pitching matchups. Indeed, of the leaders in this year’s Cy Young race, only four of the top 10 are over 30. It’s easy to forget that even veteran aces Felix Hernandez and Johnny Cueto are still only 28. With the exception of some old stalwarts like Adam Wainwright and Mark Buerhle, the game’s best and brightest seem to be tilting toward youth.

If it seems to be the case, that’s only because it is. Younger pitchers are piling up the WAR(P) at an accelerated rate relative to the past couple of decades.

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Has the Royals' new hitting coach fixed what ails their offense?

The Royals have had a roller-coaster season. No team has seemed more alternately doomed and formidable while playing to a near .500 record. Because they came into the season poised for a playoff run, with the Shields/Myers trade looming large, the stakes for the team are high. Yet, depending on the day, the team appears to be either ready to make a deep playoff run on the back of fireballing phenom Yordano Ventura or poised on the precipice of failure and an impending teardown.

Much of the anxiety imparted by the Royals stems from the performance of the so-far anemic offense, which generated higher expectations in the spring. Seemingly skilled hitters like Billy Butler and Mike Moustakas have not met their relatively optimistic projections. Without an obvious explanation (such as injury) for their underperformance, hitting coach Pedro Grifol got the axe in late May, replaced by Dale Sveum, the former Cubs skipper.

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June 17, 2014 6:00 am

Moonshot: Striking Distance

5

Robert Arthur

A look at how pitch distance from the center of the strike zone affects BABIP and power.

"To be a good hitter you've got to do one thing: Get a good ball to hit."
-Rogers Hornsby


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Tracking changes in opposing pitchers' approaches to Yasiel Puig, Jose Abreu, and George Springer.

Recently, Yasiel Puig had his one-year MLB anniversary (Puigiversary?), which caused much uproar and a deluge of odes to his ability, presumably along with a handful of curmudgeonly rants about his bat flips. Despite the seeming overabundance of press attention given to Puig, that attention is well-deserved. In his first full year, he’s become among the best players in baseball.

Almost everything there is to write about Puig’s innate ability and penchant for guffaw-inducing bloopers has already been written, and in any case, I’m already late to the Puigiversary party. I want to focus on another aspect of Puig’s performance, namely the way the league has approached him, with the hope that we can learn something about how pitchers approach young players in general. I’ve written at length about how the manner in which pitchers target hitters can inform us about those hitters. In some cases, we can forecast changes in hitter ability by observing the league’s approach to each hitter and whether it varies over the course of a season.

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June 3, 2014 6:00 am

Moonshot: What Makes Position Players Injury Prone?

5

Robert Arthur

Because pitcher injuries aren't the ONLY problem.

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Can the way a hitter is pitched help us predict a decline in performance?

There are many reasons why a player’s abilities may appear to fluctuate between seasons. Players get injured, they gain experience, and the league constantly adjusts to their particular strengths and weaknesses in real time. On top of all of the variation in skill, there is also the omnipresent addition of noise, which can make it difficult to perceive any significant shifts in ability.

But whereas the best baseball analysts are limited by the considerable volatility in things like batting average, teams have access to detailed scouting reports and the in-game experiences of some great baseball minds, namely the players themselves. I’ve written about this in my past few articles, focusing in particular on the different ways in which skilled hitters are approached by pitchers. Good hitters are rarely thrown strikes, and when a pitch does find its way into the zone, it tends to be towards the zone’s periphery. Pitchers presumably adopt this strategy in order to prevent good hitters from punishing in-zone pitches. Since pitchers have access to more and better-quality information than the general public, they might be the first to react when a batter’s true skill increases or decreases.

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