Three relief pitchers who have performed well while throwing fastballs around 90 mph

*This story was published on May 28th 2022 in Japanese.

When you think of a relief pitcher, what image comes to mind? Of course, the image may differ from person to person, but many people may think of a player like Aroldis Chapman of the Yankees, who has a high velocity fastball. Of course, relievers in MLB have a higher average velocity than starters, but some players throw fastballs around 90 mph and have outstanding results. In this article, I would like to highlight three such pitchers and look at the secret to their success.

First: Kyle Nelson (D-backs)

Defensive Rating 1.23/FIP 1.57/14.2 innings/16 strikeouts/2 walks/average fastball velocity 91.5 mph (MLB bottom 17%)

The staff that decided to acquire Nelson last November may not have expected a pitcher with a 9.31 ERA in 2021 to improve his performance so much in 2022. Nelson was drafted by the Indians in the 15th round (462nd overall) of the 2017 draft to begin his professional career. He then worked his way up the minors and made his MLB debut in 2020, making 10 starts in 2021, but as noted, his stats were dismal, including a 9.31 ERA, and he was DFA’d by the Guardians to the D-backs in November.

The secret to his success: he started throwing a slutter.

The secret to Nelson’s success is his slutter. Last year he used a slider and cutter interchangeably. However, this season, he has zeroed out his cutter and throws only a slider. And although this slider is classified as a slider, it is, in fact, a slutter, halfway between a slider and a cutter.

The chart below shows the change in each pitch type between last year and this season, and horizontally, the slider of this season is located almost halfway between the slider of the previous year and the cutter. In the horizontal direction, this season’s slider is positioned between last year’s slider and cutter.

2021 cutter Ball velocity: 88.9 mph, rpm: 2454, horizontal change: 4.7 inches

2021 Slider Ball velocity: 82.5 mph, rpm: 2670 rpm, horizontal variation: 11.1 inches

2022 Slutter Ball velocity: 84.2 mph, rpm: 2523, horizontal variation: 6.6 inches

So what has improved by changing the slider and cutter to the slutter? First, changing the cutter to the slutter improves the strikeout rate (from 23.7% to 40.2%). While the cutter is a pitch that has a reputation for getting ground balls, it is not necessarily suited for getting strikeouts. By incorporating the elements of a slider into it, he can now strike out swinging.

Another effect of changing the slider to a slutter was improving the walk rate (from 16.3% to 3.8%). At the same time, the slider has a large amount of lateral change and is an excellent strikeout pitch, if batters can recognize it, the number of pitches increases, making it more difficult to pitch. However, it has become easier to get strikes by changing to a slutter and making the amount of change smaller than that of a slider.

Second: Scott Effross (Cubs)

Defensive Rating 3.20/FIP 1.92/19.2 innings/23 strikeouts/3 walks/90.0 mph average on his fastball (bottom 7% MLB)

Effross is probably the most well-known of the three players we’ll be discussing. Effross was drafted by the Cubs in the 15th round (443rd overall) in 2015 and turned pro (his college teammate was Kyle Schwarber). He then made his MLB debut in 2021 after a successful stint in the minors and had a good season in 2021 with an 18.00 K/BB ratio in 14 games pitched. He continues to have a strong season.

The secret to his success: four different pitches

The secret to Effross’ success has been his ability to utilize his pitching repertoire. While many relief pitchers throw only two types of pitches, Effross is one of the few who throws a slider, sinker, changeup, and 4-seamer with more than 10% of the time. He is also very good at utilizing his wide variety of pitches.

First, the slider (38%) and sinker (37.7%), which account for the most significant percentage of pitches, are distinctive. Mirroring is when two pitches change directions in the exact opposite direction. The tweet below is a good reference for the image, but it is exceptionally troublesome for hitters because it moves in the same way until the middle of the pitch and then moves in the opposite direction. Efflos’ slider has a rotation direction of 9:15, and his sinker changes to 3:30, so it is mirrored with a high degree of accuracy.

An additional strength of Effros is the proximity of the horizontal variation of his sinker, 4-seam, and changeup. The picture below depicts the amount of change for each type of pitch between Effros and the league average (jagged). The horizontal variation of the 4-seam is closer to the sinker and changeup than the league average. It can be said that he throws his 4-seam and changeup to batters who are yielding to his sinker to get behind them. I think he could make further strides if he can improve on his sinker’s high .351 batting average.

Third: Cody Stashak (Twins)

3.86 ERA/FIP 2.10/16.1 innings/15 strikeouts/0 walks/90.6 mph fastball average (bottom 10% MLB)

In contrast to Effross, Stashak seems to be the least well-known of the players featured in this article. Stashak was drafted by the Twins in the 13th round (380th overall) of the 2015 draft to begin his professional career. He then established himself in the minors and made his MLB debut in 2019. He had an excellent start to his debut, but last year was a bit of a slow year, as he only pitched in 15 games.

The secret to his success is the difference in his slider’s rotation at release and when he reaches the batter’s plate.

Stashak has not changed significantly this season in any of the significant metrics compared to last year (which makes it challenging to find the reason for his strong performance). However, he has the most difference between Spin-Based Movement and Observed Movement in his slider of any right-handed pitcher, which is his weapon of choice.

First, a brief explanation of Spin-Based Movement and Observed Movement: the former indicates the rotation when the pitcher releases the ball. The latter suggests the rotation when the ball arrives at the batter’s box. Stashak’s Spin-Based Movement points to 3:15 from the batter’s perspective, which appears to be a sizeable lateral change.

However, the Observed Movement, the rotation when the ball arrives at the batter’s hand, points to 1:45, and the amount of lateral change is less than that at release. This is the tricky point. Although it looks to the batter as if a slider with a large amount of lateral change is coming at release, in reality, the slider does not break so much. Many batters are confused by this gap and strike out (the strikeout rate is 36.2%).

Stashak also has a high .370 batting average on the 4-seam, so he might improve his performance by reducing the percentage of sliders and increasing the rate of sliders, as Matt Whisler (Rays) has done.

In this issue, I have highlighted three relief pitchers who are not well-known but are performing well. We look forward to their future performance.