CSS Button No Image Css3Menu.com

Baseball Prospectus home
  
  
Click here to log in Click here for forgotten password Click here to subscribe

<< Previous Article
Premium Article On the Beat: No Excuse... (03/30)
<< Previous Column
Spinning Yarn: How Acc... (03/02)
Next Column >>
Spinning Yarn: A Soria... (04/27)
Next Article >>
Premium Article Prospects Will Break Y... (03/30)

March 30, 2011

Spinning Yarn

Do Spring Speeds Matter?

by Mike Fast

Fastball speed in the major leagues is an important and oft-researched topic. As the 2011 season begins, the trickle of reports on pitchers’ fastball speeds that came out of spring training will turn into a flood of data. Some pitchers will be throwing a little faster than they were last year, while others will have lost a notch on their hard stuff.

Do these early fastball fluctuations matter, or does a pitcher who starts slow in March and early April regain the life on his fastball later in the year? Pitchers like Joel Pineiro and Mat Latos who have lost velocity this spring seem like candidates for injury or performance drop-offs, but maybe we should start paying attention to how pitchers perform only once their teams have headed north. Does what happens in Arizona stay in Arizona? Is fastball speed in April, when the games count and the opposing hitters are all of major-league quality, what really matters?

Let’s look at how average fastball speed has changed throughout the year, as compared to a pitcher’s typical speed as measured by PITCHf/x over the 2008-2010 seasons.

Fastball speed for an average major-league pitcher starts at its lowest point in early April, rises by about 1.0-1.5 mph to a peak in the month of July, and declines gradually thereafter. These trends apply similarly to starting pitchers and relief pitchers. However, the fastball speed curve looks suspiciously like a graph of temperature.

Fastball speed has a strong dependence on temperature, irrespective of the point in the season.

If we approximate the relationship between temperature and fastball speed as linear, we find that average fastball speed increases by about one mph for every 37-degree increase in game-time temperature.

Adjusting for temperature removes some, but not all, of the seasonal pattern.

Interestingly, the 2008 season still shows a noticeable increase of nearly one mph from April to July, whereas the 2009 and 2010 seasons have much flatter fastball speed profiles once temperature effects are removed. The origin of the differences in profiles between seasons is unknown.

Some PITCHf/x fastball speed data hails from outside the regular season. The limited amount of such data makes a date-based comparison too noisy to be useful, but the overall temperature-adjusted fastball speed as compared to the regular season average is as follows:

 

Type of Game

Fastball Speed Delta (mph)

Regular season

0.0

Postponed (rainout, etc.)

+0.2

Playoff

+0.3

All-Star Game

+1.1

Spring training

-0.6

2009 World Baseball Classic

-0.6

Arizona Fall League

0.0

 

There are some challenges in applying these league-wide results to individual pitchers. Foremost among them is PITCHf/x camera calibration, which varies over time and from park to park. My method for correcting pitch location data to account for camera calibration problems was detailed here, and I used a similar method to correct fastball speed data.

The extent to which spring training fastball speeds are predictive of regular season fastball speeds is of particular interest. PITCHf/x data is collected from two spring training sites, Surprise and Peoria, Arizona, which play home to the Texas Rangers, Kansas City Royals, San Diego Padres, and Seattle Mariners. PITCHf/x information from spring training is primarily available for those four clubs and their visiting Cactus League opponents. Thus, PITCHf/x data from Grapefruit League teams is mostly nonexistent. Another smattering of spring training PITCHf/x data is available from the handful of exhibition games played in major-league ballparks prior to opening day.

If we look at fastball speed data collected in spring training last season, we can compare the speeds for individual pitchers to their average fastball speeds in September 2009. Then we can see how well this difference predicted the individual pitcher’s fastball speed for the 2010 regular season.

There is definitely a predictive relationship between the fastball speed change observed in spring training and the fastball speed change observed in the regular season. Pitchers on average retained 41% of their spring training speed changes into the regular season, and the correlation coefficient for the sample here is r=0.53.

The pitchers with the biggest changes in fastball speed from September 2009 to spring training 2010 are as follows.

 

Pitcher

Average Fastball Speed (mph)

Change from Sept. 2009

Sept. 2009

Spring 2010

2010

Spring 2010

2010

C.J. Wilson

92.8

89.6

90.0

-3.2

-2.9

Jonathan Broxton

96.2

93.3

95.0

-2.9

-1.3

Jerry Blevins

89.8

87.2

88.9

-2.6

-1.0

Daisuke Matsuzaka

89.4

86.9

90.5

-2.4

+1.2

Jeff Samardzija

93.9

91.5

92.3

-2.4

-1.6

Mike Pelfrey

93.0

90.6

91.6

-2.4

-1.4

Paul Maholm

88.0

85.8

87.7

-2.2

-0.2

Darren O’Day

84.7

82.6

85.1

-2.2

+0.4

Brett Myers

90.3

88.1

88.4

-2.2

-1.9

Rich Harden

91.4

89.3

90.3

-2.1

-1.1

 

 

 

 

 

Tommy Hanson

90.4

92.3

91.8

+1.9

+1.4

Brian Bannister

86.7

88.7

88.2

+1.9

+1.4

Leo Rosales

89.6

91.6

89.8

+2.0

+0.3

Billy Wagner

92.5

94.8

94.1

+2.3

+1.6

Felix Hernandez

92.7

95.1

93.2

+2.4

+0.5

Gavin Floyd

89.3

91.7

89.9

+2.4

+0.5

Denny Bautista

92.7

95.1

94.1

+2.4

+1.4

Josh Towers

85.4

87.9

--

+2.6

--

Santiago Casilla

92.3

95.2

96.1

+2.9

+3.8

Brett Anderson

91.6

94.5

91.6

+3.0

+0.0

 

Many, but not all, of the spring training fastball speed changes presaged a similar change in the regular season. Some of them, of course, have relatively harmless explanations. For example, C.J. Wilson lost three mph while transitioning from the bullpen to the starting rotation.

Since spring training data collection is so limited, perhaps early regular-season data, which is collected for every team and every pitcher, would be a better predictor of ultimate fastball speed across the full upcoming season. Let’s compare the fastball speed changes observed in the first two weeks of the 2010 regular season as compared to September 2009 to the fastball speed changes observed in the remainder of the 2010 season as compared to September 2009.

The correlation does appear to be a little stronger here, with pitchers on average retaining 52% of their early April speed changes, with a correlation coefficient of r=0.66. Let’s look at some of the individual pitchers.

 

Pitcher

Average Fastball Speed (mph)

Change from Sept. 2009

Sept. 2009

Apr 4-17, 2010

2010

Apr 4-17, 2010

2010

Miguel Batista

92.2

88.9

90.1

-3.3

-2.1

Phil Hughes

92.8

89.9

91.1

-2.9

-1.7

Jose Valverde

94.3

91.8

93.3

-2.7

-1.0

C.J. Wilson

92.8

90.3

89.9

-2.5

-2.9

Garrett Mock

90.7

88.3

--

-2.4

--

Jeff Samardzija

93.9

91.7

92.4

-2.2

-1.5

Andy Sonnanstine

86.9

84.7

85.6

-2.2

-1.3

John Grabow

88.5

86.2

87.6

-2.2

-0.9

Mike Pelfrey

93.0

90.8

91.7

-2.1

-1.3

Christopher Volstad

93.1

91.0

90.1

-2.1

-3.0

 

 

 

 

 

Carlos Villanueva

87.5

89.6

88.9

+2.2

+1.5

Jensen Lewis

87.7

89.8

88.2

+2.2

+0.6

Aaron Laffey

86.8

89.0

86.9

+2.2

+0.1

Tyler Clippard

89.1

91.3

90.2

+2.2

+1.1

Mitchell Boggs

93.1

95.3

95.1

+2.2

+2.1

Tim Stauffer

88.7

91.0

90.5

+2.2

+1.7

Luke Hochevar

90.0

92.4

91.3

+2.4

+1.4

Charlie Morton

90.9

93.5

92.3

+2.6

+1.4

Jered Weaver

87.5

90.2

88.9

+2.7

+1.4

Tommy Hanson

90.4

90.4

91.7

+2.8

+1.3

 

There are some players with real velocity changes on the list above, but there are also some examples that reveal the shortcomings of a blind reliance on this method while using an automated pitch classification system. Valverde is the obvious problem here, as his fastball speed didn’t really change much from 2009 to 2010. Instead, the Major League Baseball Advanced Media (MLBAM) pitch classifier had trouble separating his fastballs from his splitters in the early part of 2010. Batista and Hughes both greatly increased their cut fastball usage from September 2009 to April 2010, and since I included cutters when calculating average fastball speed, their speeds show a decrease due to changing pitch mixes.

As spring training draws to a close in 2011, which pitchers have displayed the greatest fastball speed changes this year among those Cactus League pitchers for whom there is PITCHf/x data?

 

Pitcher

Average Fastball Speed (mph)

Change from Sept. 2010

Sept. 2010

Spring 2011

Justin James

93.4

89.7

-3.6

Ted Lilly

86.6

83.3

-3.5

Santiago Casilla

96.3

93.2

-3.1

Joel Pineiro

87.3

84.6

-2.7

Ernesto Frieri

91.8

89.2

-2.6

Neftali Feliz

96.1

93.6

-2.5

Aaron Heilman

91.6

89.4

-2.2

Tim Stauffer

91.0

88.8

-2.1

Manny Delcarmen

90.3

88.2

-2.1

Yovanni Gallardo

93.0

91.0

-2.0

 

 

 

Joakim Soria

88.7

90.1

+1.4

Mike MacDougal

93.7

95.1

+1.4

Jesse Chavez

92.1

93.6

+1.5

Pat Neshek

85.0

86.6

+1.5

Mark Lowe

92.9

94.5

+1.6

Luke Hochevar

90.5

92.2

+1.6

Jonathan Sanchez

89.6

91.3

+1.7

Jordan Norberto

91.9

91.9

+1.7

Kerry Wood

92.8

95.3

+2.5

Chris Seddon

86.2

89.6

+3.5

 

Feliz’s fastball speed presumably dropped because of his latest experiment with starting. Some of the other changes may also have innocent explanations upon further investigation. Moreover, this list may not capture some of the subtler indications of trouble hidden in the fastball speed data.

For example, Harry Pavlidis identified a troubling decrease in Latos’ fastball speed during spring training, but his overall average speed change does not stand out as much as the decrease over time. Latos had an average fastball speed of 93.0 mph in September 2010. In spring training this year, his four PITCHf/x-recorded starts had average fastball speeds of 93.7, 93.4, 91.6, and 91.6 mph, after adjusting for temperature and camera calibration. Now comes news that Latos has inflammation in his right shoulder.

Changes in fastball speed offer promise as a diagnostic and predictive tool, but there are pitfalls to avoid, and our techniques for separating the wheat from the chaff must be improved. It will be interesting to see whether pitchers such as Lilly, Pineiro, and Latos recover their lost velocity and go on to successful seasons or whether they will have to work against injury and slower fastball speeds in 2011.

Methodological improvements are needed to adjust for changes in pitch mix between fastball types and to account more carefully for atmospheric changes that affect the drag coefficient of the ball. Nonetheless, there appears to be substantial value in the current form of this data.

Mike Fast is an author of Baseball Prospectus. 
Click here to see Mike's other articles. You can contact Mike by clicking here

Related Content:  Spring Training,  Speed,  3-0 Count,  Fastball,  Pitch Speed

15 comments have been left for this article. (Click to hide comments)

BP Comment Quick Links

Bodhizefa

Drool-worthy stuff, Mike. This is exactly the type of material I was hoping you'd cover in your Pitch F/X dissection, and I wasn't disappointed. I hope I'm not alone in suggesting you perform follow-ups on data like this throughout the season if you find any outliers occurring for any substantial period. Letting us know who is seeing velocity upticks or downticks could be crucial pre-breakout or pre-injury intel that would be great from a fantasy perspective.

Mar 30, 2011 07:00 AM
rating: 4
 
studes
(280)

Good stuff, Mike. The graph breaking out different years is pretty interesting. Worth staring at.

So, is the correlation between temperature and fastball speed 100% real (occurs on the pitcher level) or might it also impact the PITCHf/x recordings?

BTW, I hope that's good news for Kerry Wood.

Mar 30, 2011 07:08 AM
rating: 3
 
BP staff member Mike Fast
BP staff

Thanks, Dave. I believe the correlation between temperature and fastball speed is partly real, occurring at the pitcher level. There is a portion of it which is a measurement/methodology artifact, probably about half of the effect that I reported here. I need to spend a bit more time figuring that out, but here's what I know right now.

The fastball speeds that I report in this article are based on the speeds measured at home plate. That helps remove a lot of the measurement error due to PITCHf/x camera calibration. I then increased the speeds by a flat 8% multiplier to get back to the standard 50-foot distance, assuming an average drag coefficient. The drag coefficient varies with temperature (and with altitude and properties of the individual baseball, etc.). A baseball going 91.8 mph when 50 feet from the plate will be going 85 mph at the plate with average temperature and altitude. A baseball going 92.3 mph when 50 feet from the plate will be going 85 mph if the temperature is 37 degrees below average because the denser air will slow it down more.

So about half the effect that I report above is probably due to air resistance changes and about half the effect is probably real.

I have some methods to correct pitch speeds for changing drag coefficients, but I haven't applied to this analysis yet.

One thing that gives me some reassurance in claiming that increased temperature helps pitchers throw harder is that the home pitcher, coming straight from warming up in the bullpen, throws harder in the first inning than does the visiting pitcher, who must go sit on the bench for a half inning before entering the game. The difference is nearly one mph in favor of the home-team pitcher, and it evaporates completely after the first inning.

Mar 30, 2011 07:31 AM
 
BP staff member Mike Fast
BP staff

I should clarify that when I say that the fastball speeds that I report in this article are based on the speeds measured at home plate, I mean that, unless I said otherwise, that's the speed used. In some cases, where noted, I temperature adjusted the speeds, and toward the end of the article, where I'm comparing from previous seasons to spring training, I also adjusted the plate speeds for camera calibration errors. (The camera calibration is better near home plate, but it's not perfect there, either.)

Mar 30, 2011 07:36 AM
 
Sky Kalkman

Hot damn, Mr. Fast, this is fantastic.

Mar 30, 2011 07:32 AM
rating: 0
 
msloftus

I keep reading articles explaining Phil Hughes has lost a bunch of ticks off his fastball, and was sitting around 87-88 mph this spring. Is this indicative of him using his cutter more, or something else?

Mar 30, 2011 09:14 AM
rating: 0
 
BP staff member Mike Fast
BP staff

I don't know. His cutter is normally around 88, and his four-seam fastball is around 92-93. Unfortunately there is no PITCHf/x data from Florida spring training sites, so I don't have any data to give you a better answer than what you already have.

Mar 30, 2011 09:36 AM
 
msloftus

Thanks Mike. I guess we will know shortly if he is okay or not.

Mar 30, 2011 13:59 PM
rating: 0
 
Alan Nathan

Not to be too technical here, but it is not the drag coefficient that depends on temperature but the drag itself. Mike knows this and just said it wrong.

Now a question: What if you do the analysis using the release speed (i.e., at 50 ft) rather than the home plate speed. If you do this, do you see half of the temperature effect (based on your comment that the temperature dependence of the drag accounts for half of the observed effect)?

Mar 30, 2011 15:21 PM
rating: 0
 
BP staff member Mike Fast
BP staff

Yes, thanks for the correction, Alan. I meant the air density or the drag, not the drag coefficient.

I have not done the analysis using the release speed, but that is on my list of things to do.

Mar 31, 2011 13:44 PM
 
BP staff member Mike Fast
BP staff

Alan, I've taken a look at this now, and I do see about half the effect due to temperature when I look at release speed (50 ft). I see an effect of 1 mph per 70 degrees F.

Apr 27, 2011 06:56 AM
 
evo34

Pretty interesting. Looking forward to more of this during the season. One observation is that run scoring is actually positively correlated with temp., so the reduced air resistance appears to benefit hitters even more than the added velocity benefits pitchers.

How was the population chosen for the temp. analysis? You only used guys who played the whole season I assume?

Mar 31, 2011 02:20 AM
rating: 0
 
BP staff member Mike Fast
BP staff

I used all players who pitched in more than one game. That will bias the sample a little bit with the data from pitchers who only pitched in games in a certain small temperature range, but I don't think the effect is very significant. It will be a good idea to test that assumption, though.

Mar 31, 2011 13:47 PM
 
Alan Nathan

My expectation would be that hitters benefit much more from reduced air resistance than pitchers. Witness the Coors Field effect. In that case, the reduced air resistance is due to altitude rather than temperature.

Another interesting thing to look at is the movement of the pitch (pfx_x,pfx_z) as a function of temperature. At higher temperatures, just as the lower air density reduces the drag, it also reduces the movement due to the spin. The difference in movement between Coors and the other stadiums is very clearcut from PITCHf/x data. The temperature effect would be more difficult to pull out but it might be worth a try.

Mar 31, 2011 08:57 AM
rating: 0
 
Travis G.

Phil Hughes was a reliever in 2009, which explains part (most?) of his velocity drop in '10.

Apr 02, 2011 22:00 PM
rating: 0
 
You must be a Premium subscriber to post a comment.
Not a subscriber? Sign up today!
<< Previous Article
Premium Article On the Beat: No Excuse... (03/30)
<< Previous Column
Spinning Yarn: How Acc... (03/02)
Next Column >>
Spinning Yarn: A Soria... (04/27)
Next Article >>
Premium Article Prospects Will Break Y... (03/30)

RECENTLY AT BASEBALL PROSPECTUS
Premium Article League Preview Series
Every Team's Moneyball: Minnesota Twins: Reb...
Premium Article Skewed Left: History Repeats Itself
Premium Article League Preview Series
Premium Article Pitching Backward: Why Relievers Get A Free ...
Premium Article Spring Training Notebook: Cactus League
Prospectus Feature: How the Astros do Spring...

MORE FROM MARCH 30, 2011
Premium Article Prospects Will Break Your Heart: An Embarras...
Premium Article On the Beat: No Excuses
Premium Article Collateral Damage: Disabled on Opening Day
Fantasy Article Fantasy Focus: Down the Rabbit Hole
Fantasy Article Fantasy Beat: Spring Hurlers
Fantasy Article Fantasy Beat: Value Picks in the Outfield
The BP Wayback Machine: Baseball's Hilbert P...

MORE BY MIKE FAST
2011-04-27 - Spinning Yarn: A Soria Subject
2011-04-12 - BP Unfiltered: Early PITCHf/x Ballpark Speed...
2011-04-07 - BP Unfiltered: In the Beginning...
2011-03-30 - Spinning Yarn: Do Spring Speeds Matter?
2011-03-29 - BP Unfiltered: Community Playing Time Foreca...
2011-03-20 - BP Unfiltered: Pineiro Shoulder Tightness
2011-03-11 - BP Unfiltered: You Are the Weekend Links
More...

MORE SPINNING YARN
2011-06-01 - Spinning Yarn: The Real Strike Zone, Part 2
2011-05-11 - Spinning Yarn: Speed Traps
2011-04-27 - Spinning Yarn: A Soria Subject
2011-03-30 - Spinning Yarn: Do Spring Speeds Matter?
2011-03-02 - Spinning Yarn: How Accurate is PitchTrax?
2011-02-16 - Spinning Yarn: The Real Strike Zone
2011-01-19 - Premium Article Spinning Yarn: Rafael Soriano in King Mo's C...
More...

INCOMING ARTICLE LINKS
2014-04-14 - Premium Article Moonshot: Does April Velocity Last?
2011-08-26 - Baseball ProGUESTus: Do Pitchers Really Trad...
2011-04-04 - Premium Article Collateral Damage: Checking into the Hollida...
2011-04-01 - What You Missed: 3/28-4/1