Spin Trends by Pitching Staff

With the 2019 season firmly in the books and the expanded offering of spin-related pitching data now readily available across the internet, I decided it was time to take a hard look at every team’s pitching staff. The hope in doing so was to identify a trend, if any, within the spin metrics of the best clubs. Do any staffs have a noticeable tendency to use pitchers with a specific spin profile?

To answer this, I pulled together every pitcher and their average spin metrics for each pitch type that they threw a qualified amount of times (30-plus in most cases) in 2019. This meant ignoring splitters because of sample size considerations. I was also tempted to use Bauer Units — a proxy for spin rate divided by velocity, as well as a nod to Trevor Bauer — to control for velocity in this study, but I decided to keep this post more straightforward. The study instead uses raw spin rate, horizontal and vertical movement, and spin efficiency as reported by Baseball Savant. I then aggregated the players’ data by the team they finished the season with to create an average spin profile for every team. This team profile weighs all of their qualified pitchers equally.

Once I was able to establish what the normal team looks like across those categories, I wanted to identify any clear outliers to possibly show where organizations consciously emphasized certain metrics. To do that, I produced league rankings and standard deviations for each category based on the team averages.

To establish the significance of these factors, I also tagged each team with the average of all their players’ xwOBA within the sample instead of overall team xwOBA so that we don’t give too much credit to teams that were carried by just a couple of workhorse starters. Here are the rankings of the top three teams in a few key areas: FF Vertical Movement, CH Horizontal Movement, SL Spin Rate, CU Spin Efficiency, and CU Spin Rate.

One thing that was expected but became painfully obvious when building this study is that the Houston Astros have the secret sauce. Across the 23 categories that were observed, Houston had a top-five finish in 11 of them, while the average team had fewer than four. But whereas the Astros find themselves right at the top of the xwOBA standings by being great at absolutely everything, the Dodgers and Rays have matched them in a more specialized way.

The common theme for the teams mentioned above (and the other top teams) is having efficient fastballs. In fact, five of the top six teams are more than one standard deviation above the average in FF spin efficiency. Tampa Bay, armed with FFs that rise far more (2+ Std Dev) than any other team’s, represents another common type of club we find at the top of the league: one with devastating sliders.

Below is the slider spin rate, efficiency (%), and vertical/horizontal movement (reported as % Break versus the average pitch at a similar velocity) of the top performing teams:

The cells highlighted indicate where a team was at least one deviation away from league average. I do want to note a few things here. First, Tampa Bay had only six qualified sliders on their staff compared to the league average of 11, but those six are absolute frisbees thanks to the work of Chaz Roe and company. Secondly, the Dodgers and Athletics are average performers here but have a strong combination of highly efficient fastballs and curveballs that may help explain their success.

Finally, creating depth with sliders did not seem to drive performance in the rankings, much to the dismay of the Atlanta Braves, who were the runaway leaders in that category yet only finished 15th in terms of average xwOBA. One of the best slider-throwing teams may have been hampered by underperforming fastballs:

The other pitches I have not mentioned yet (sinkers, cutters, and changeups) were much harder to define in this study. The main reason for this was that there are multiple combinations of spin rate, efficiency, and direction that will produce better outcomes. For instance, evidence shows that higher spin rates and efficiency for FFs and CUs generally improves performance, but that is not always the case when dealing with sinkers and changeups. The effectiveness of these pitches is more reliant on the context of the pitcher, which leads to a lot of murkiness, so I decided not to write about it this time around.

Again, the hope for this study was to identify trends in the top performing teams and possibly uncover what they are doing strategically. I think the Cincinnati Reds are a prime example where we may have done just that. I don’t believe many people expected their pitching staff to go from 24th in Team ERA in 2018 to 8th in 2019. What exactly did they do this year? Yes, they went and got a stud in Bauer. But what did they do well as a team?

Above are the two pitches where they found themselves considerably better than average. As you saw earlier, they have filthy horizontal sliders that average 30% more break than other pitchers. But more interestingly, they are by far the league leaders in horizontal run for FFs. In fact, at 32.9%, they are almost three deviations above average. This FF-SL combination is truly unique across the entire league.

Obviously there are a ton of other factors outside of spin profiles that play into the Reds’ and all the top teams’ success, and this study has its limitations (especially with sample size), but that doesn’t mean we can’t gain some interesting insights. To support that statement, I want to call attention to the fact that the Reds made the most interesting hire of the offseason in making Driveline Baseball founder Kyle Boddy — a guy known for data-driven training and pitch design concepts — their Director of Pitching Initiatives/Pitching Coordinator at the beginning of October.

Just two weeks later, the Reds quietly made an odd waiver claim. They picked up Josh D. Smith, a 30-year-old lefty with 12 career innings and a fastball that averages just over 90 mph who was just cut by the Marlins. What do the Reds see in him? It probably has something to do with the spin rate of his fastball (2645 rpm) and slider (3016 rpm), which rank 5th and 6th respectively among all pitchers regardless of velocity on the Statcast leaderboard. They also both have exceptional horizontal movement. Finally, his fastball spin efficiency is reported at 70.8%, almost a full 12 points below the league average of 82%, meaning he hasn’t even come close to realizing the fullest potential movement of his fastball.

Josh, meet Kyle.

We hoped you liked reading Spin Trends by Pitching Staff by Jacob Foster!

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VERY good.