As Eduardo Rodriguez became somewhat of a star during the 2019 season, I began to admire his rise to becoming a reliable big-league starter. One aspect of his game that I really started to pay attention to was his changeup. Building on that, the efficiency he was able to have while using that pitch in a specific location was baffling and extraordinary in my eyes.

Why so important?

First, though, I want to start this with some history. In the past, lots of people in the baseball community have talked about how most hurlers don’t throw pitches down and in to the same-handed batter. But some prominent pitchers have found success in their careers by doing such. Moreso, many people over the years have actually suggested that throwing a pitch, specifically changeups, down and in to the same-handed batter is just asking for trouble. Of course, in more recent years, this idea has been refuted and almost effectively reversed. But after reading about this pitch phenomenon, and doing more research on it myself, I found that Eduardo Rodriguez’s pitch specifics exactly match this new-era zone theory.

Rodriguez’s zone-specific changeup expressed by data

Thanks to Baseball Savant, and recently available play-by-play data, I was able to select all of these changeups that were thrown down and in vs. LHH. With this data, it is now possible to numerically value just how effective the placement of this pitch was when thrown by Eddie in 2019. He threw 56 of these such pitches in 2019, which is a relatively small sample size but I wanted to highlight the efficiency of this pitch specifically in the following season. Only six of those 56 were even put into play, three resulted in field outs, one a fielders choice, and two resulted in home runs. The two home runs are not ideal, but my point with this post is to just mainly highlight how little balls are hit into play in the first place because, in my eyes, that’s what makes a pitch so lethally efficient.

To further showcase the low contact rate of this pitch are the numbers provided with these splits on Baseball Savant. With this pitch, Rodriguez sported 41 swings on 56 pitches, a 73.2% Sw%, as well as 20 whiffs, for an almost 50% Whiff%. This accounts for a .249 wOBA and .125 BA against on this specific Rodriguez pitch type and zone placement.

Here is one such example of Eddie’s nasty pitch to lefties from 2019, featured on the Pitching Ninja Twitter account:

An overall devastating pitch

Not only was his changeup effective when thrown in the specific zone earlier highlighted in this piece, but it was also his most effective pitch overall in 2019. His changeup was not hit often, but when it was hit, players couldn’t do much damage. In 2019, players showcased a SLG% of only .360 against the pitch. And the average exit velocity when hit was 83 MPH, the lowest of any of his pitch types. This data remains relatively the same through the 2017 and ’18 seasons, with the usage percentages of the pitch remaining similar throughout the years as well. This shows an upward trend of changeup efficiency for Rodriguez.

With this, Rodriguez’s elite 2019 changeup also earned itself a .258 xWOBA overall on Baseball Savant’s pitch info, which comes in third behind only his soft contact inducing sinker (.249), and rarely deployed curveball (.226). What all of this data tells us is that Rodriguez has found himself an out-inducing pitch that also allows for an incredibly high soft-contact rate, which is plenty useful in today’s league.

Groundballs produced a new Eddie in 2019

Furthermore, his 2019 changeup boasted a 68% groundball %, which is comparable to Dallas Keuchel’s 2019 sinker GB% of 70.7%. It is amazing that Rodriguez could turn this into such an out-inducing pitch that it shows rates similar to that of groundball-master Dallas Keuchel’s infamous sinker. This groundball rate is what really allowed for Rodriguez’s changeup to produce the results it did in 2019., as he only had a 38.7% overall groundball rate in 2018. A jump this big could mean big things for Eddie, and the Sox’, future. Hopefully, for Rodriguez, this changeup efficiency trend continues as it has in the past couple of years. If Eddie could up the usage of this pitch even more without its effectiveness dropping, it could be the key to cementing his place in the Sox starting rotation for years to come.