Bye Bye Fastballs and Curveballs, Hello Sliders

Yesterday, I dove into some of the hitting metrics to determine what has been driving the decline in offense. Today, let’s over to the pitching side and review another set of metrics. Obviously, we use a lot of the same metrics on each side, so I’ll only present and discuss those that weren’t shared yesterday.

ERA/SIERA Trend
Season LOB% ERA SIERA
2018 72.8% 4.15 4.06
2019 72.3% 4.51 4.41
2020 71.8% 4.45 4.34
2021 72.1% 4.27 4.18
2022 72.3% 3.75 3.61

Let’s start with one of the metrics I include in the “luck” trio for pitchers that wasn’t included yesterday (BABIP & HR/FB already discussed), LOB%. This metric “measures the percentage of base runners that a pitcher strands on base over the course of a season”, according to our glossary. You might be asking why I lump it in as a luck metric, as you would expect better pitchers to record higher LOB% marks. This is generally true. However, what happens when the pitcher is taken out of the game mid-inning with runners on base? Suddenly, LOB% is no longer in that pitcher’s control, but instead in the reliever’s who has just been summoned. That’s one important piece of the luck element, as now the pitcher is relying on his reliever to strand his runners.

A higher or lower LOB% can have a big impact on ERA because it has a direct relationship. A lower LOB% indicates more baserunners scored, raising ERA, and vice versa. From the trend, we see a slight increase off 2020 and 2021, but in line with 2019. So pitchers aren’t really stranding more runners than usual.

That 3.75 ERA is the lowest since 2014, which matches with the last year that HR/FB rate was in the single digits. Obviously, home run rate has a significant impact on run scoring. We only calculate SIERA going back to 2002, but this year is the lowest going back that far. Yes, it’s even lower than in 2014, when it sat at 3.67. That’s probably because it doesn’t use actual HR/FB rate and this year’s strikeout rate is significantly higher than back in.

Now let’s see if pitchers have adjusted their pitch mix any. If you read the article title, you have already figured out the answer.

Pitch Mix Trend
Season FA% FC% FS% SI% CH% SL% CU%
2018 36.3% 5.8% 1.7% 17.9% 10.2% 16.9% 10.1%
2019 36.7% 6.0% 1.6% 15.1% 10.8% 18.3% 10.3%
2020 35.2% 6.4% 1.8% 15.2% 11.7% 18.7% 10.7%
2021 36.3% 6.4% 1.6% 14.8% 11.2% 19.9% 9.7%
2022 34.4% 6.5% 1.7% 14.4% 11.3% 22.7% 8.9%

Our Pitch Info pitch mix data goes back to 2008. Pitchers have thrown the lowest rate of four-seam fastballs since 2012, and the second lowest since we have data for. Cutters have taken a very slight jump up and have now reached its highest since 2015. That’s interesting because since that year, usage had declined and fell below 6% for two years, before rebounding. Splitter usage has been quite consistent ever since dipping below 2% in 2016, and never jumping back in. That’s surprising since splitters generate one of the highest SwStk% marks. I’m guessing that it’s just a difficult pitch to master, even though it’s so effective once mastered.

The decline in sinker usage continues, as it has hit another new season line. Can you believe that through 2015, sinker usage was over 20%?! It dipped into the high teens in 2016 and then quickly dropped further. Teams and pitchers must have realized that pitching to contact isn’t an ideal path to success. The pitch typically generates a low SwStk%, but lots of ground balls. That means lots of balls in play, 29% of which will typically fall for a hit.

Changeup usage has been on the rise, beginning around 9% in 2008 and having remained above 11% for three straight seasons now. It’s an important pitch to throw to neutralize opposite-handed batters.

Then there’s the slider. It’s one of the most enjoyable pitches to watch when it’s thrown well and also owns one of the highest SwStk% marks on average. Its usage has nearly doubled since 2008! This year would mark the eighth straight season of increased slider usage, which is just nuts. The increase has accelerated too, jumping nearly three percentage points this year to push above 20% for the first time.

Finally, pitchers have been ditching the curveball, as its usage is the lowest its been since our first year of data in 2008. Usage was over 10% for four straight years during 2017-2020, so I’m not sure what happened. It’s possible that the sticky stuff ban made it more difficult to get the same movement on the pitch and so pitchers opted to throw something else. But I would expect a similar impact on sliders, so I’m really not sure.

So bottom line is that pitchers are throwing their four-seamers, sinkers, and curveballs less often, in favor of sliders.

Have velocities continued to increase? Let’s find out.

Pitch Velocity Trend
Season vFA vFC vFS vSI vCH vSL vCU
2018 93.2 88.7 84.8 92.3 84.3 84.4 78.9
2019 93.5 88.6 85.0 92.5 84.6 84.6 79.0
2020 93.5 88.2 85.2 92.7 84.6 84.3 79.3
2021 93.8 88.5 85.9 93.1 84.9 84.7 79.3
2022 94.0 89.1 86.5 93.1 85.4 84.3 79.3

Yes, yes they have. Even with a shortened spring training, this is the highest four-seam, cutter, splitter, sinker, changeup, and curveball velocity in our data going back to 2008. Oddly, slider velocity is actually down! That’s quite surprising considering usage is at an all-time high from the data we have. Usually, increased velocity goes for all pitches, so it’s weird to learn that every pitch’s velocity is up, while the pitch pitchers are throwing more often is actually down. Just adds to the bizareness of the 2022 season!





Mike Podhorzer is the 2015 Fantasy Sports Writers Association Baseball Writer of the Year. He produces player projections using his own forecasting system and is the author of the eBook Projecting X 2.0: How to Forecast Baseball Player Performance, which teaches you how to project players yourself. His projections helped him win the inaugural 2013 Tout Wars mixed draft league. Follow Mike on Twitter @MikePodhorzer and contact him via email.

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VottomanEmpiremember
6 days ago

Slider velo going down may be a feature of teams introducing more medium-velo, horizontal-break-emphasizing “sweeper” sliders and fewer tight, high-velo “gyro” sliders?