Mark Prior @ USC

I'm sure everyone knows the Mark Prior history, so I won't go into it. Carlos Gomez at Hardball Times has done a piece on Prior's mechanics, and I disagree with how he analyzes pitchers. To be fair, he follows the mechanics of Paul Nyman (SETPRO) and I am more of a Bill Peterson/Chris O'Leary/Mike Marshall and Tom House analyst.

Carlos and I agree on a few things, however:

1) Building momentum into footplant. We both agree that pitchers who are quick down the hill from maximum leg lift should theoretically throw harder and take some stress off the arm. By being fast into footplant, you make it tougher for runners to steal, you limit your arm action duration (giving you less time to develop flaws), and develop momentum towards home plate.

2) Good followthrough is important. A strong, aggressive finish gives the arm time to decelerate over the body and limit injury. To use a racing analogy, if you had a Corvette Z06 that was 100 feet from a cliff, you'd only be able to go so fast before you slammed on the brakes to stop yourself from flying off the cliff. The better the brakes, the faster you can theoretically go before stopping. By strengthening your decelerator muscles and by having a long and complete finish, you are effectively giving yourself more room to drive.

Here is a slow-motion clip of Mark Prior (alongside Pedro Martinez; we'll ignore him for the purposes of this analysis):

Here are some of his major flaws:

1) Pitcher forearm flyout. This is a Marshall-derived term that carries a lot of negative connotation. Regardless, Chris O'Leary has done analysis of pitchers who exhibit this flaw, and they tend to suffer arm injuries more frequently than pitchers who do not (Greg Maddux, Tom Glavine). Forearm flyout occurs when a pitcher reverse rotates his acromial line more than perpendicular to the plate (assuming the traditional motion). The acromial line is a line drawn from shoulder to shoulder and would look like a level balanced across your upper body. In other words, reverse rotation past perpendicular is when you turn the shoulders away from home plate, perhaps reaching towards third base with the glove arm if you're a right-handed pitcher. For an extreme example, think Hideo Nomo with the big back turn. Mark Prior reverse rotates his shoulders as he accelerates to the plate, which causes...

2) ...his arm to be late. Prior is late in getting to the high-cocked position. Watch the short pause in the clip when his foot lands. His arm has not yet reached the "ready" position and arrives late to the party. Here's a still photo that shows the ugliness more accurately:

This is what Chris O'Leary calls the Inverted W. This is a major timing flaw, and puts unnecessary stress on the labrum/rotator cuff muscles.

3) As he progressed through the MLB, his tempo slowed down. Carlos Gomez already broke this down, which can be seen in this clip:

I'll let Carlos explain:

 

Quote:

The idea is this. The faster you are with your body towards the plate, the more momentum you build into footplant and the less work your arm has to do to produce 95+mph force. You'll jump farther from a running start than from a walking start. It's pretty much the same principle at work here.

A lot of this post has been previously written about, and I mainly just agree with what many people have said. I wanted to bring it to the attention of 2+2 and long-suffering Cubs fans, some of who blame Prior for a poor work ethic. Let me assure you, no work ethic could overcome these "perfect" mechanics.