Data, Data Visualization

Edwin Diaz Dashboard

By Jon Elordi

I was recently sent this article from FanGraphs. The article was meant to inspire a blog post. Well, it did. Mission accomplished Salem. I decided to make a dashboard in Tableau about Edwin Diaz’s pitching. I have pushed it to Tableau Public, here.

Edwin Diaz is the closer for the Seattle Mariners. He has a league-leading 27 saves and is the owner of a 2.37 ERA. Here’s how he does it.

He features three pitches. Two different types of fastballs as 2-Seam and a 4-Seam. He has one offspeed pitch and it’s a slider. The pitch spread is what you would expect from a righty with this pitch arsenal. Throwing the fastball high and inside to right, with the slider breaking down and away.


At a glance, it looks like he uses his 4-Seamer in the same way he uses 2-Seamer. The average location of each pitch is very similar further verifying this point.

Overall Diaz throws his 2-seamer and slider about 40% of the time, and only throwing his 4-seamer 20% of the time. The pitch usage changes depending on the count he’s in. With a Full count, he throws his slider a majority of the time. 56% to be precise. And rarely throws his 4-seamer.

With three balls, a very friendly hitters count, he get’s away from his slider and throws a fastball of some kind 65% of the time. He’s trying to throw strikes to get the count more in his favor. While in a two-strike pitchers count, He favors his slider far more. This suggests that his slider is his strikeout pitch. Meaning that his goal is to set batters up with his fastball. then when the batters are expecting another fastball, he throws a slider tricking the batter into striking out.

Looking at pitches in an at-bat, the 4-seamer’s use continuously decreases. The share of sliders increases for the first three pitches. Interestingly, on the fourth pitch sees a break in that pattern. the share of sliders decreases and the 2-seamer is used more often. This is likely due to getting into 3-0 counts. That fourth pitch needs to be a strike and he is likely to pitch the ball in the strike zone with a fastball.

The pitch used by pitch count tells a similar story. As Diaz gets more strikes the use of his slider increases. The slider is what he likes to go to get batters to swing and miss. Furthermore, we see that he has avoided hitters counts. He get’s into a 2-0 and 3-0 count only 5% of the time. Conversely 10% of the batters he faces fall into a 2-0 pitchers count.

His slider has quite a bit of movement to it. The slider is typically eight inches lower and eight inches to the right of his fastball. Or about elven inches away as the bird flies, thank you, Pythagoras. One thing that is really helping the success of his slider is that it has practically the same release point as his fastball. By contrast, Justin Verlander has some distance between the release points of his pitches.

Justin’s fastball is thrown higher and closer to his body than his slider or his curveball. Justin’s average fastball release is 5 inches away from his average slider release point. Diaz’s difference is only 2.7 inches.

Diaz’s success stems from his fastball-slider combination. the slider has plenty of movement and is thrown from almost the exact release point as the fastball. This has been a productive combination for him. Another aspect of his success has been his ability to avoid hitter’s counts as he rarely get’s into 2-0 and 3-0 counts. These two factors are why he is seeing too much success this season.