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The White Sox and Spin

by Kyle Wood

The 2020 season for the White Sox has wrapped up, and as we move towards the offseason, it is time to analyze what they currently have and figure out a way to make the current players that will return next season better. The offense was one of the best in the league and the defense was much improved, so that leaves the pitching staff as the lowest hanging fruit.

The pitching staff has two main issues. The first, the harder of the two to improve, is control. The White Sox were 21st in the league in BB% in 2020, and that is not indicative of a pitching staff that is poised to get deep into October. They were also outside of the top 10 in K% (14th), so they are not keeping runners off base with a high K rate. The second issue has to deal with pitch metrics such as total spin, active spin, as it’s called by Statcast, and Bauer Units.

Before getting into my analysis of the team, I’d like to define and discuss some terms. Total Spin is fairly easy to understand, as it is the amount of raw spin on a baseball – it does not matter if it is backspin or gyro spin. Backspin is typically what someone sees on a fastball, whereas gyro spin would be like the spin of a bullet or football. Fastballs, and really any other pitch, can have some or a lot of gyro spin. This is where we get into active spin. Active Spin is the percentage of spin that contributes to movement, meaning for a fastball it would be the backspin. When it comes to fastballs you want as much back spin as possible, as gyro spin prevents as much movement as possible, as you’ll see later. But for example, a fastball with a 2,200 spin rate that has 200 rpm of gyro spin would have an Active Spin or Spin Efficiency of 90.9. Bauer Units is simply the Total Spin divided by the pitch velocity. This was a metric obviously created by Trevor Bauer that normalizes fastball effectiveness. The reason to normalize it is so you can compare pitchers with fastballs that vary in velocity. For example, the MLB average fastball is 93 with a spin rate of 2,267, which comes out to a Bauer unit of 24.38. This fastball would be expected to have a similar movement profile to that of a 95mph fastball with a spin rate of 2,316rpm.

Team/LeagueFF Avg VeloFF Avg SpinBauer Unit
White Sox Average*94.13225623.98
MLB Average93226824.38
*6 White Sox pitchers from 2020 that will be on the roster in 2021 and throw 4 seam fastballs. This includes Cease, Giolito, Lopez, Foster, Cordero, and Keuchel.

As you can see in the table above, the team has above average velocity, but below average spin rate. Hopefully this offseason, the pitchers currently on the staff can improve their fastballs to catch up to or even surpass league average. With all of this out of the way, I can now analyze a few individual players and explain how they can improve for the 2021 season.

Dylan Cease

To start off, I’d like to say that I fully believe that Cease can be a front of the rotation starter, but he has a couple things he needs to work on to get there and I believe he can improve at least one of the issues this offseason. His issues are the same as I stated above for the entire pitching staff, control and spin. Control can definitely be improved, but it is difficult and can take a long time. His walk rate was the highest in MLB at 13.3% and does not strike out enough hitters (17.3% K rate) to sustain that kind of walk rate and maintain a solid ERA. Spin metrics however can be improved in as short as a couple bullpen sessions, let alone an entire offseason and spring training.

Last NameFirst NameFF Avg VeloFF Avg SpinActive SpinActive Spin RankingSpin Percentile RankingBauer Unit

As we already know and as the table shows above, he has elite fastball velocity. On top of that he has an elite amount of Total Spin, shown by his 94 percentile rank among all MLB pitchers. In comparison with the MLB average, his fastball should be more effective than the average pitcher based on Bauer Units. But total spin and velocity are not the only attributes of a pitch. Active Spin is just as important as the aforementioned metrics. Dylan has a low Active Spin percentage of 75.2, meaning of the 2521 rpm on his fastball, only 1,896 is contributing to pitch movment, and ranks 463rd among pitchers in 2020. He has mentioned that he “cuts” his fastball a lot, which means his hand gets more on the side of the ball than behind it and was also touched on by our Jordan Lazowski before here:

Having a low Spin Efficiency leads to a flatter fastball, and I would like to see Dylan Cease get it up to at least 90, if not 95%. Now I know this can be difficult to visualize, so I added a video to help you understand the difference below:

Current fastball on the left, what it would look like at 95% spin efficiency on the right.

Now that we know what can be improved on his fastball, what can he do to improve it? Like I mentioned earlier, the reason for cutting the ball is that he gets on the side of the ball instead of behind it. Using tools such as a Rapsodo and any high-speed camera, whether it’s on your phone or a high end camera like an Edgertronic, a pitcher can get instant visual feedback from video of his hand position and the efficiency and movement profile from the Rapsodo. Once he tweaks his hand position and sees how the efficiency changes with the feel of the position change, he can continuously throw more until that hand position becomes ingrained.

Reynaldo Lopez

Such is the theme of this article, you can probably guess that ReyLo has two main issues: control and spin. Lopez had a walk rate of 12.4% in 2020, not much lower than Cease. With that being said his spin issues are different from Dylan’s, and may actually be harder to improve. Lopez has very good Active Spin at 88.9. So he isn’t cutting his fastball, but his Total Spin is below average at 2137rpm and a Bauer Unit of just 22.71. Like I said, improving Total Spin can be more difficult than Active Spin. One of the ways that I have come across is grip strength training. Rock climbing and other forearm/hand exercises have been promoted by some to improve spin rate. This makes sense as improving grip strength would help a pitcher with their feel of the ball.

Last NameFirst NameFF Avg VeloFF Avg SpinActive SpinActive Spin RankingSpin Percentile RankingBauer Unit

Jimmy Cordero

Jimmy does not have as bad of control issues as the others, and his walk rate is lower than I thought it would be at 7.3%. He also has a very good Active Spin of 90.1. The problem is that he has worse spin than Lopez. Spin increases with velocity within pitchers, but not between them. This means that different pitchers can throw at the same velocity and have largely different spin rates, but for example if a pitcher throws 93 with a 2,200 spin rate, he would be expected to increase his spin rate if his velocity increased. So while Cordero’s fastball is 3mph faster than Lopez’s at 97.1 on average, his spin rate is slightly worse at 2,131. This gives him a Bauer Unit of 21.95, which is a below average fastball. The ways to improve Cordero’s Total Spin would be the same as I described for Lopez.

Last NameFirst NameFF Avg VeloFF Avg SpinActive SpinActive Spin RankingSpin Percentile RankingBauer Unit

Now you should have a solid understanding of where the White Sox stand on their pitching staff, what they need to improve on, and how they can improve before factoring in free agency. These improvements should make them a stronger contender for a World Series going into the 2021 season.

All stats are from FanGraphs and pitch metrics and rankings from Baseball Savant.

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James Clemens

Your comments and analysis are interesting,but I am too old to learn the new statistical measures.In my work before retiring,I used stats on a daily basis. Anyway,I still rely on ERA and WHIP when thinking about pitching performance.
IMO. the Sox need a pitching coach who is truly a part of the Sox rebuild.Many of the newer pitchers were mentored by Matt Zeleski in the minors and don’t seem to respond well to Don Cooper.I think we would see immediate improvement.

Dale Cole

Interesting comment about Zeleski. It seems to me that the above info clearly shows in most cases the pitchers’ weaknesses and what they need to do to become better pitchers. It is up to the pitching coaches and the players to work on the fundamentals and make the needed changes to become more effective. Giolito did it and other star pitchers have and are adding new pitches to become more effective. It is time for Cease and others to show thw work ethic that Giolito did.

Chris G

Exceptional article. One of the best ones that I have read in quite a while. As perhaps a follow up, and for comparison purposes, it would be great to see Giolito’s metrics since it seems like he gets a lot of carry on his fastball.

James Clemens

Your information is clear and well presented.
It sounds as though Dylan Cease needs to reclaim his old approach to throwing his fastball.
Saw him pitch in Winston-Salem and his rising fastball looked great He seemed like a young Verlander back then.Is the’ cut ‘on his fastball limiting spin rate and reducing effectivness?

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