Pitcher Injury Factors: Literature Review & Rankings Update

Note: About 95% of this article was finished before the news that MLB is going forward with a 60 game season.  I finished it knowing that more imporant work needs to be done. This series now comes to an abrupt end and I will return to the series once the season is over one way or the other.

I’m continuing my quest to predict pitcher injuries and their effects as best as possible. I started grinding through the process last week and found through some additional work that injuries from just the past two seasons drag down production. Today, I’m going to go over some other possible other injury causes and provide updated injury ranks.

While I’ve done quite a bit of my own work on pitcher injuries, I decided to scour the web come up with some new ideas. Here are some possible ideas ranked by how I’d like to investigate them.

First off, from my previous work, I haven’t found any non-fastball (e.g. slider) to be cause for MLB injuries. While some articles I read point to some pitch types causing injuries, but once fastball velocity is equalized, I can’t find any relationship.

1. Lack of mobility

Inside Pitch Online brings up the idea of mobility.

We need to help the body achieve more athletic positions in the delivery with mobility work. Mobility is “the ability to move freely into a desired position” and can be something that is lost fairly quickly. In fact, many athletes don’t even realize they’re losing it until they’re injured. If you combine a loss of shoulder and hip mobility with the violence of the pitching movement, you can get a recipe for disaster. On the other hand, not all athletes need extensive mobility work. Those with laxity (excessive joint range of motion) need more stability to help them get into more athletic positions. For these guys some foam rolling, scapular stability work and good old-fashioned strength training may be just what the doctor ordered.

Building off my work on hitter athletism, I’ve always wondered if the work can be applied to pitchers. The pitcher’s defense can be measured but with a universal DH likely to be implemented, it’s tough to get any batting information in the future thereby making the past results useless.

1A. Lack of preseason ramp-up period.

A few sources point out that a short preseason could be the problem. Inside Pitch Online made their case.

Sometimes too little of a good thing can be detrimental as well. Many older, more experienced players—especially the guys that already have commitments to schools—may be trying to save some bullets and start throwing a little later, and ramp up a little slower. Players go from a casual off-season progression to an excessive amount of high intensity pitches in a short amount of time. In the northeast, this is especially taxing since the season usually begins in 40-degree weather. It is a grind. If you are a high-level pitcher and you aren’t familiar with Davis’s Law, you should be: “Ligaments, or any soft tissue, when put under even a moderate degree of tension, if that tension is unremitting, will elongate by the addition of new material; on the contrary, when ligaments, or rather soft tissue, remain interruptedly in a loose or lax state, they will gradually shorten, as the effete material is removed, until they come to maintain the same relation to the bony structures with which they are united that they did before their shortening.”

And then Mike Reinold made his:

So considering that injuries are higher during the first month of the season, what could be the reason for this? I think there are probably two reasons why we see so many Tommy John surgeries near the beginning of the season: 1) poor preparation, and 2) lingering issues.

I think a big factor is preparation for the season. Over the last two decades we have improved offseason strength and conditioning. I don’t think it is that players are sitting around on the couch all offseason. Rather, I think it has more to do with their throwing programs.

There are two ends of the spectrum, the established player that knows that they have a spot on the roster, and the player trying to make the team. For the player trying to make the team, they need to show up on day one of camp ready to go and ready to impress.

Preseason warmup is another factor I’m not 100% sure on how to measure. The best I can come up with is Spring Training pitches and/or innings to show the amount warmup.

3. Strike throwers

I’ve examined strike throwers several times with mixed results. The key has been in-season changes but I need to rule out any seasonal predictive value.

4. Injuries and extension

This nugget from the Nationals was shown to me a while back and it’s something I haven’t looked into yet.

The Nationals did exhaustive research on Scherzer before signing him to a seven-year, $210 million free agent contract in Jan. of 2015. Part of their scope was his pitching mechanics and whether they would someday lead to injuries.

The Nationals’ medical staff determined at the time he was likely to avoid Tommy John surgery and other serious problems due to the fact he releases the ball further out in front of his body than many of his peers. Though pitching mechanics and predicting injuries combine to be an inexact science, the Nats have since been proven right.

I only have extension data from the past five seasons but it shouldn’t be too hard to affirm it or rule it out.

5. Time between pitches

Another study that I could easily perform is the time between pitches using Pace.

The simulation showed that using the pitch clock caused greater arm fatigue –seven per cent more.

Increasing muscle fatigue, which is already known to be one of the primary causes of injury to pitchers, can reduce the natural stiffness of the elbow joint, leading to greater strain on the ulnar collateral ligament, or UCL, the ligament which is torn and repaired during the so-called ‘Tommy John Surgery.’

6. Max versus average velocity

While I’ve dived into average fastball velocity, maybe top speed is more important.

Though in Andrews’ interview he cites throwing curveballs and sliders as potentially increasing the likelihood of elbow injury, he is likely referring more to younger athletes who are not physically mature and whose mechanics may be faulty. It is generally understood that, in the pro ranks, fastball pitchers – who throw at an increased velocity – generate forces that place the greatest strain on the structures of the elbow and forearm. Thus there is danger in consistently throwing at maximum effort.

The doctor does point out an interesting conundrum, however, in that “players with higher velocity have longer careers and also perform better. Therefore, it would be unrealistic to recommend that pitchers simply not throw as hard. However, varying speeds might improve a pitcher’s effectiveness and conceivably also reduce injury risk.”

Another study that’s easy to test but has a huge overlap with my average fastball work.

7. Torque generated

Arm torque was listed everywhere but without access to individual players, there is no way to collect the data.

Deficits in preseason shoulder range of motion and strength were significant risk factors for general arm or shoulder injury among high school and professional players. Elbow and shoulder varus torque at peak external shoulder rotation during pitching, high pitch velocity, and shoulder rotational and flexion deficits were risk factors for elbow injuries among professional pitchers.

I wanted to include it because it’s a missing component.

Other

Besides finding some more possible injury-related areas to investigate, here are my latest rankings for injury chances and the aging effects. In the comments, William Wallace pointed out that I need to divide out the factors that cause rapid aging from those that can lead to more injuries. Right now, there is quite a bit overlap with the only difference being a high fastball velocity leads to injuries and IL time over the past two seasons leads to a drop in skills.

Pitcher Injury Risk Factors
name Age FBv Career IL Days IL days in Past 2 Seasons Total Arm Injuries IL Chance Factors Increase Aging Factors
Yu Darvish 32 94.2 492 137 5 4 4
Adam Wainwright 37 89.9 608 157 4 3 4
Brett Anderson 31 90.8 918 66 6 3 4
Charlie Morton 35 94.4 551 10 4 4 3
Clay Buchholz 34 89.5 591 172 2 3 4
Homer Bailey 33 93.0 626 52 8 3 4
Hyun-Jin Ryu 류현진 32 90.6 537 125 4 3 4
Jason Vargas 36 84.3 638 82 3 3 4
Rich Hill 39 90.3 549 168 5 3 4
Carlos Carrasco 32 93.5 344 107 5 3 3
Edinson Volquez 35 93.4 339 149 2 3 3
James Paxton 30 95.5 336 59 2 3 3
Martin Perez 28 94.1 377 82 5 3 3
Matt Harvey 30 93.2 384 49 4 3 3
Michael Pineda 30 92.6 489 22 4 3 3
Michael Wacha 27 93.1 217 113 2 3 3
Nathan Eovaldi 29 97.5 377 156 4 3 3
Shelby Miller 28 94.3 265 79 2 3 3
Stephen Strasburg 30 93.9 421 68 6 3 3
Taijuan Walker 26 93.3 355 358 2 3 3
Alex Wood 28 90.0 148 68 3 2 3
Andrew Cashner 32 93.9 375 19 4 3 2
Andrew Heaney 28 92.5 333 101 2 2 3
Anibal Sanchez 35 90.5 415 53 5 2 3
Brady Rodgers 28 91.4 216 187 2 2 3
Carlos Rodon 26 91.5 188 224 3 2 3
Clayton Kershaw 31 90.4 196 68 2 2 3
Clayton Richard 35 90.4 265 140 2 2 3
Cole Hamels 35 91.4 147 35 4 2 3
Danny Duffy 30 92.4 354 70 6 2 3
David Price 33 92.0 155 44 3 2 3
Drew Pomeranz 30 92.7 141 82 5 2 3
Edwin Jackson 35 93.4 122 26 2 3 2
Felix Hernandez 33 89.6 209 115 3 2 3
Gerrit Cole 28 97.2 143 0 4 3 2
JC Ramirez 30 91.0 219 304 2 2 3
Jeff Samardzija 34 91.9 139 139 2 2 3
Jeremy Hellickson 32 88.5 186 153 2 2 3
Jhoulys Chacin 31 90.0 252 48 3 2 3
Jimmy Nelson 30 92.7 216 315 2 2 3
Joe Ross 26 94.1 159 0 2 3 2
Jordan Zimmermann 33 90.5 223 105 2 2 3
Lance Lynn 32 94.2 249 0 2 3 2
Masahiro Tanaka 30 91.5 157 31 2 2 3
Matt Moore 30 93.0 309 187 3 2 3
Matt Shoemaker 32 90.5 289 315 2 2 3
Mike Soroka 21 92.5 129 129 2 2 3
Nathan Karns 31 90.5 382 295 2 2 3
Nick Tropeano 28 90.8 360 136 5 2 3
Paul Blackburn 25 90.6 196 157 2 2 3
Steven Matz 28 93.4 231 26 4 3 2
Trevor Cahill 31 91.7 203 55 3 2 3
Tyler Skaggs 27 91.4 417 65 2 2 3
Tyson Ross 32 90.0 358 142 3 2 3
Vince Velasquez 27 94.1 127 27 3 3 2
Zack Wheeler 29 96.7 446 14 4 3 2
Aaron Nola 26 92.9 143 0 2 2 2
Aaron Sanchez 26 93.6 259 103 0 2 2
Anthony DeSclafani 29 94.7 318 68 1 2 2
Chris Sale 30 93.2 77 80 3 2 2
Derek Holland 32 92.4 366 20 2 2 2
Dinelson Lamet 26 96.1 188 289 1 2 2
Drew Smyly 30 91.2 340 15 2 2 2
Eduardo Rodriguez 26 93.1 162 59 0 2 2
Ivan Nova 32 92.4 299 13 4 2 2
J.A. Happ 36 91.3 263 7 2 2 2
Kevin Gausman 28 94.0 66 51 2 2 2
Mike Foltynewicz 27 94.9 51 42 2 2 2
Mike Minor 31 92.6 397 0 3 2 2
Noah Syndergaard 26 97.7 199 68 0 2 2
Patrick Corbin 29 91.9 272 0 2 2 2
Alex Cobb 31 92.3 351 180 1 1 2
CC Sabathia 38 89.2 312 75 1 1 2
Collin McHugh 32 90.8 131 64 1 1 2
Erick Fedde 26 92.3 88 61 2 1 2
Ervin Santana 36 90.1 270 162 1 1 2
Frankie Montas 26 96.6 183 0 0 2 1
Jacob deGrom 31 96.9 22 17 2 2 1
Jake Arrieta 33 92.5 91 49 2 1 2
Jerad Eickhoff 28 89.5 208 234 0 1 2
Joe Musgrove 26 92.4 76 60 2 1 2
Jordan Montgomery 26 91.7 153 327 1 1 2
Jose De Leon 26 92.2 187 373 1 1 2
Madison Bumgarner 29 91.4 153 68 0 1 2
Marco Estrada 35 87.4 140 142 0 1 2
Marcus Stroman 28 92.5 217 58 1 1 2
Matt Strahm 27 91.5 132 48 0 1 2
Sean Manaea 27 89.8 70 197 3 1 2
Sonny Gray 29 93.3 96 0 3 2 1
Zach Davies 26 88.5 104 120 2 1 2
Blake Snell 26 95.6 12 79 1 1 1
Brandon Woodruff 26 96.3 0 57 0 1 1
Chris Archer 30 94.1 34 92 0 1 1
German Marquez 24 95.5 0 38 0 1 1
Jake Faria 25 93.6 99 70 0 1 1
Jameson Taillon 27 94.8 54 149 1 1 1
Jeff Hoffman 26 93.7 31 31 1 1 1
Jon Gray 27 96.1 96 40 0 1 1
Jon Lester 35 90.3 146 16 0 1 1
Jose Urena 27 95.9 40 96 1 1 1
Luis Severino 25 96.1 16 176 1 1 1
Luke Weaver 25 93.9 0 117 0 1 1
Max Scherzer 34 94.9 22 42 1 1 1
Mike Clevinger 28 95.5 0 79 0 1 1
Pablo Lopez 23 93.6 31 108 1 1 1
Trevor Bauer 28 94.6 38 38 0 1 1
Tyler Anderson 29 91.3 280 15 0 1 1
Tyler Glasnow 25 97.0 35 120 1 1 1
Tyler Mahle 24 93.3 0 33 0 1 1
Yohander Mendez 24 93.8 0 151 0 1 1
Zack Greinke 35 90.0 188 0 1 1 1
Antonio Senzatela 24 93.7 22 29 1 1 0
Brad Keller 23 93.4 0 0 0 1 0
Brett Martin 24 93.9 0 0 0 1 0
Brian Johnson 28 88.9 28 113 0 0 1
Cal Quantrill 24 94.5 0 0 0 1 0
Caleb Smith 27 91.6 117 99 1 0 1
Chris Flexen 플렉센 24 94.3 0 0 0 1 0
Chris Paddack 23 93.9 0 0 0 1 0
Cody Reed 26 94.2 28 0 0 1 0
Corbin Burnes 24 95.2 0 0 0 1 0
Corey Kluber 33 91.6 61 151 0 0 1
Daniel Ponce de Leon 27 93.4 0 0 0 1 0
Enyel De Los Santos 23 93.3 0 0 0 1 0
Eric Skoglund 26 89.7 101 101 1 0 1
Felix Pena 29 91.5 0 57 0 0 1
Freddy Peralta 23 93.6 0 16 0 1 0
Gio Gonzalez 33 89.3 31 49 1 0 1
Gregory Soto 24 95.4 0 0 0 1 0
Jack Flaherty 23 93.9 0 0 0 1 0
Jeff Brigham 27 96.6 0 0 0 1 0
Jesus Tinoco 24 93.9 0 0 0 1 0
Joey Lucchesi 26 90.2 36 36 0 0 1
Jon Duplantier 24 92.2 0 37 0 0 1
Jorge Lopez 26 94.2 0 0 0 1 0
Josh Rogers 24 89.5 0 96 0 0 1
Julio Urias 22 95.2 0 0 0 1 0
Justin Verlander 36 94.7 69 0 1 1 0
Kyle Freeland 26 91.9 10 41 0 0 1
Kyle Gibson 31 93.3 48 9 1 1 0
Kyle Wright 23 94.6 0 0 0 1 0
Lucas Giolito 24 94.3 0 30 0 1 0
Luis Castillo 26 96.5 0 0 0 1 0
Luis Ortiz 23 94.1 0 0 0 1 0
Miles Mikolas 30 93.6 0 0 0 1 0
Mitch Keller 23 95.4 0 0 0 1 0
Nick Pivetta 26 94.6 0 0 0 1 0
Pedro Avila 22 93.6 0 0 0 1 0
Reynaldo Lopez 25 95.5 14 0 0 1 0
Robbie Ray 27 92.4 84 68 0 0 1
Ryan Borucki 25 92.0 0 183 0 0 1
Sandy Alcantara 23 95.6 0 0 0 1 0
Sean Newcomb 26 94.4 0 6 0 1 0
Shane Bieber 24 93.1 0 0 0 1 0
Touki Toussaint 23 93.5 0 0 0 1 0
Trevor Williams 27 91.3 0 33 0 0 1
Wade LeBlanc 34 86.1 14 34 0 0 1
Wade Miley 32 90.5 83 64 1 0 1
Walker Buehler 24 96.6 16 16 0 1 0
Yency Almonte 25 95.7 0 0 0 1 0
Zach Eflin 25 93.6 112 18 1 1 0
Alec Mills 27 89.7 0 0 0 0 0
Andrew Suarez 26 92.8 0 0 0 0 0
Ben Lively 라이블리 27 92.4 0 0 0 0 0
Corey Oswalt 25 91.6 0 0 0 0 0
Dallas Keuchel 31 88.4 63 0 0 0 0
Daniel Mengden 26 91.2 64 17 0 0 0
David Hess 25 93.0 0 0 0 0 0
Dereck Rodriguez 27 90.6 7 7 0 0 0
Dillon Peters 26 91.1 0 0 0 0 0
Dylan Bundy 26 91.2 20 20 1 0 0
Eric Lauer 24 91.9 30 30 1 0 0
Framber Valdez 25 93.0 0 0 0 0 0
Jaime Barria 22 91.7 0 0 0 0 0
Jake Odorizzi 29 92.9 65 10 0 0 0
Jakob Junis 26 91.5 13 13 0 0 0
Jalen Beeks 25 92.2 0 0 0 0 0
Jordan Yamamoto 23 91.5 0 27 0 0 0
Jose Berrios 25 92.8 0 0 0 0 0
Jose Quintana 30 91.4 0 0 0 0 0
Julio Teheran 28 89.7 28 11 0 0 0
Justus Sheffield 23 92.8 0 0 0 0 0
Kenta Maeda 31 92.1 28 23 0 0 0
Kolby Allard 21 92.5 0 0 0 0 0
Kyle Hendricks 29 86.9 49 17 0 0 0
Kyle McGowin 27 91.0 0 0 0 0 0
Logan Allen 22 92.7 0 0 0 0 0
Marco Gonzales 27 88.9 15 15 0 0 0
Matthew Boyd 28 92.0 0 0 0 0 0
Mike Fiers 34 90.4 11 11 0 0 0
Mike Leake 31 88.4 51 0 1 0 0
Mike Wright 라이트 Jr. 29 92.9 34 0 0 0 0
Nick Margevicius 23 88.3 0 0 0 0 0
Rick Porcello 30 90.5 27 0 1 0 0
Ryan Carpenter 28 90.0 0 0 0 0 0
Sean Reid-Foley 23 92.6 0 0 0 0 0
Tanner Roark 32 92.1 0 0 0 0 0
Thomas Pannone 25 89.8 0 0 0 0 0
Trevor Richards 26 90.9 0 0 0 0 0
Yusei Kikuchi 28 92.5 0 0 0 0 0
Zack Godley 29 90.0 0 0 0 0 0





Jeff, one of the authors of the fantasy baseball guide,The Process, writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won three FSWA Awards including on for his MASH series. In his first two seasons in Tout Wars, he's won the H2H league and mixed auction league. Follow him on Twitter @jeffwzimmerman.

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docgooden85
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docgooden85

“using the pitch clock caused greater arm fatigue”

Perhaps this causation is backwards. Someone who is tired or injured is pretty obviously going to take more time to recover between pitches than someone who isn’t.

delatopia
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delatopia

I love this kind of thinking, taking assumptions and conclusions and turning them over and looking at them from a different angle. It’s like the arrival of the first stat geeks who said in SI that running the ball is the key to winning football, and the smart readers who wrote in saying you run because you’re winning, not the other way around.