Phillies 2015 Best Pitches, Part I

What makes an offering by a pitcher in Major League Baseball, in particular someone from the 2015 Philadelphia Phillies pitching staff, a “good pitch”, effective on a consistent basis?

Today we’ll explore the question, and explain some of the methods that I used to evaluate those 2015 Phillies hurlers. Tomorrow, I’ll actually present the list of which five pitches from which pitchers made the cut as the five best this past season.

What does it for you in evaluating a pitch? Is it movement, such as the kind delivered by a moundsman which elicits a response from a TV analyst that a certain curveball is “falling off the table“, or that the pitcher’s slider is “biting” that day?

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Is it opposition batter reactions, such as when a hitter is so far out in front of a changeup that he corkscrews himself into the ground, futilely swinging at the offering?

Could it be the consequences of a batter making contact with the pitch, such as memorable images of Mariano Rivera sending bat after bat after bat to an untimely demise, shattered by his famous cutter?

Maybe it’s a ridiculous stat line which the pitch produces, such as those the Fox network comes up with during the postseason, revealing the futility of hitter outcomes when facing a particular offering from a particular pitcher.

However you choose to view it, there are many pitches that we know are just “filthy”, frequently unhittable. The aforementioned cutter from Rivera. Randy Johnson‘s slider. Greg Maddux‘ or Pedro Martinez‘ changeup. These were pitches that dominated their career highlight reels, and showed up in the stat line as being highly effective against the competition.

I decided to not just use the “eye test”, but to use some statistical evaluation to examine which pitches may have been thrown by Phillies’ hurlers during this past 2015 season which were the most effective against the competition.

The goal was to reveal which particular pitches thrown by which pitchers, while perhaps not in the pantheon of the all-time greats mentioned here previously, were still highly effective for the 2015 Phillies’ arms against opposing hitters.

Aug 10, 2015; Phoenix, AZ, USA;

Philadelphia Phillies starting pitcher Harang (34) throws during the first inning against the Arizona Diamondbacks at Chase Field.

(Photo Credit: Matt Kartozian-USA TODAY Sports)

So that you can see exactly what I was looking for, here are the parameters that I chose to utilize in making the evaluations.

First, pitchers had to have tossed at least 25 innings as a reliever, or 75 innings as a starter. These were arbitrarily selected. But with all of the turnover that the rotation and bullpen experienced this year, 75 and 25 seemed about right. Those levels tend to separate those who were just September call-ups from those pitchers who actually made a significant contribution to the outcome of the Phillies 2015 season.

Second, I decided to use the following slash line – batting average/slugging/isolated slugging (BAA/SLG/ISO) to introduce each pitcher. These numbers show the damage done by opposing hitters when they did make contact against a Phillies pitcher.

There seems to be some disagreement between the two major sites dedicated to PitchF/x – Brooks Baseball and Fangraphs, when breaking down pitch effectiveness. Each has their own view of what defines each pitches, and each provides evidence as to the damage done accordingly.

However, while Fangraphs does provide OBP (on-base percentage) numbers for individual pitches, I was more interested in what actually happened when a ball was hit, and thus my choice of the BAA/SLG/ISO slash-line.

Finally, I was keenly aware of sample size. For instance, Jake Diekman‘s sinker was thrown less often than Aaron Harang‘s was thrown while with the Phillies in the 2015 season. However, that sinker is Diekman’s primary offering. Since he is a reliever, the fact that he features the pitch more often must be taken into account.

Comparing relief pitcher’s offerings to a starting pitcher’s tosses would be a little one-sided. Relievers generally don’t need to hold anything back. Therefore, their fastballs are usually going to be more difficult to hit, as they don’t have to save anything in reserve for the next and future innings. I took that factor into account when breaking down the pitches.

A final note: while Sean O’Sullivan was only slightly less effective with his changeup than Cole Hamels was, there will not be any mention of O’Sullivan on the list, because he was such a poor pitcher overall. To make an appearance, that overall effectiveness was also taken into account.

So there is the setup for what will be tomorrow’s presentation of the most effective pitches delivered by those who toed the rubber in red pinstripes at Citizens Bank Park this past season, the Phillies five best pitches of 2015.

Next: Three Phils FA Pitching Possibilities

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