Most Effective Pitch Repertoires

The Question: Who Wields Their Weapons the Best?

In our last post, we looked which pitch combos are effective and being used effectively. This study showed us that there are definitely 1-2 pitch combos that are creating the most value for pitchers, and some that are letting hitters eat their probabilistic lunch.

So, given that we know:

• Some pitch combos are far more effective than others, and
• Pitchers use ineffective pitch combos far more than they should,

The next natural question is: who is using their entire repertoire of pitch combos the best?

The Pitch Combo Portfolio

This is best answered by looking at each pitcher’s observed pitch combos and packaging them as a portfolio of combos, with each combo weighted by how much it is used relative to others. Thus, the weighted average output of this calculation gives us a pitcher’s Combo wOBA Added across their entire portfolio of pitch combos. The better the pitcher’s combos, and the more often he uses those combos, then the lower the pitcher’s Combo Repertoire wOBA Added.

The chart below displays where individual pitchers sit on this measure of effectiveness. The X-Axis is the Combo Repertoire wOBA Added, and the Y-Axis is the sample size of combos we have for that pitcher (e.g. show who the innings eaters are).

Who Wields Their Weapons the Best?

In looking at the insights from the tool above, we can learn a few things:

Greater Volume of Pitches -> Gravitation to Neutral Outcomes

The greater the sample size of combos observed in our sample, which has a direct relationship with pitches thrown, the more likely pitchers are to be closer to 0.000 on their Repertoire wOBA Added (see the blue trend line in the graphs).

Better Pitchers Fall to the Left of Zero

I’ve cherry-picked a few examples below of pitchers who have negative Combo Repertoire wOBA Added. Yes, these guys are cherry-picked; no, this is not a robust correlation analysis; and yes, they are close to zero. However, the quality of the names demonstrates that there could be a there there; and they are closer to zero because they were workhorses for their teams (see analysis above).

So What’s the Practical Implication?

This is an iterative step in understanding the dynamics at play in pitch sequencing. Coaching a pitcher to “have a better Combo Repertoire wOBA Added” isn’t helpful. However, understanding that this is a critical determinant in pitcher success is helpful so that we can seek to understand the deeper dynamics better and use those in the pitch sequencing decisions.

So, more to come.