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.