Are Returning Pitchers Throwing Harder?

© Dale Zanine-USA TODAY Sports

As you might imagine, I watch a lot of baseball for work, and one of the things that stands out to me the most this year is just how dang hard pitchers are throwing. I’m not just talking about that new hotshot reliever your team called up who’s dropping triple digits like peak Aroldis Chapman, though that’s part of it. I’m talking about existing starters, guys I’ve watched for years, adding a little oomph.

Max Fried has topped out over 100 mph this year; his teammate Kyle Wright has never thrown harder. Framber Valdez is up nearly two ticks on average. Carlos Rodón already threw hard, and now he throws even harder. You can’t walk 10 feet without tripping over a pitcher throwing harder than ever – or so it seems to me, a fairly interested observer.

But appearances can be deceiving. I can think of any number of baseball truths that were considered evidently true by observation for years, only to later be disproven. I decided to put my eyes to the test. Have pitchers learned how to throw harder from one year to the next, changing the fundamental truth of how aging works? Let’s find out.

My method is fairly simple. I took every starter who threw at least 10 innings since pitch-level data began in 2008. I took their average four-seam fastball velocity, but only in games they started; I didn’t want to have swingmen who changed roles within or between seasons in my data. From there, I looked at every pitcher to see if he’d thrown in the majors the previous year, and if so, the change in fastball velocity from one year to the next.

In this way, I got a yearly sample of how much every returning pitcher in baseball’s velocity changed, on average, every year. As a quick example, there were 176 pitchers who compiled at least 10 innings as a starter in both 2013 and ’14. On average, they threw 0.21 mph slower in 2014 than they did in ’13. I found those pairs for every year, which gave me a yearly average of velocity changes over time.

Let’s get the headline out of the way first: 2022 doesn’t look any different than previous seasons. On average, starters have lost 0.06 mph of fastball velocity this year. That’s slightly better than the -0.13 mph average over the entire sample, but hardly out of line with the past few years. My uninformed guess that pitchers have a newfound ability to maintain or add velocity appears to be false:

Returning SP Velo Change by Year
Year Average Change (mph)
2009 0.10
2010 -0.25
2011 -0.11
2012 -0.09
2013 -0.02
2014 -0.21
2015 -0.28
2016 -0.10
2017 -0.31
2018 -0.40
2019 -0.10
2020 -0.06
2021 0.04
2022 -0.06

Frustrating! A little anecdotal evidence didn’t highlight a new and provable insight about the game. But just to make sure, I decided to look at the numbers split out a few more ways. Were more starters adding velocity now, with some large velocity losers hiding that trend in the averages up above? As it turns out, no. In fact, fewer starters than average have added velocity this year:

Returning Starters Adding FB Velo
Year % Adding Velo
2009 48.0%
2010 39.8%
2011 40.7%
2012 41.8%
2013 40.4%
2014 38.6%
2015 44.3%
2016 37.9%
2017 39.0%
2018 29.0%
2019 46.7%
2020 46.1%
2021 49.3%
2022 37.9%

Okay, fine, it looks very much like nothing new is happening this year. Pitchers are the same as always. Maybe a few outliers have muscled up and started throwing much harder, but that’s the case nearly every year. Even if I limit my search to pitchers who added at least one full tick to their fastball, there’s nothing out of the ordinary about 2022.

Just to close the loop, I decided to separate pitchers by age and see if I was missing anything there. Maybe a big cohort of aging pitchers was confusing the data from one year to the next. I made three groups – 25 and under, 26 to 30, and over 30 – and looked at each group’s average velocity change by year:

FB Velo Change by Age, Year
Year <=25 26-30 31+
2009 0.25 0.06 -0.01
2010 -0.10 -0.32 -0.29
2011 -0.12 -0.04 -0.26
2012 0.17 -0.06 -0.48
2013 -0.07 0.00 -0.02
2014 -0.31 -0.11 -0.32
2015 -0.13 -0.18 -0.56
2016 0.09 -0.29 0.07
2017 0.06 -0.48 -0.40
2018 -0.30 -0.31 -0.60
2019 0.22 -0.17 -0.15
2020 0.17 0.00 -0.33
2021 0.34 -0.03 -0.10
2022 0.05 0.00 -0.26

There’s still not much here. There’s a sample issue in comparing between groups – pitchers in the 31-plus tier are more likely to retire, and they’re probably more likely to retire when they lose a ton of velocity from one season to the next. That creates a population issue; the older pitchers that we see probably aren’t representative of the population of all older pitchers.

Even if you compare within a tier, there are no clean takeaways. Pitchers between 26 and 30 have gained velocity this year, but not very much, and not in a way that’s clearly different from pitchers aged 26-30 in previous years (p=0.18 in a two-sided Student’s t-test). Mostly, I was just seeing ghosts.

Of course, a study like this can’t disprove that new training methods are helping pitchers maintain and add velocity. That’s a central truth of statistics when used in this way; all you can do is fail to disprove the null hypothesis (that pitchers are the same as ever). Maybe there’s a new trend developing, and maybe the evidence will become obvious over time, or maybe there’s simply a falling attrition rate. If pitchers who would have previously lost two ticks of velocity and retired now lose one tick and stay in the league, improved training methods could actually decrease average velocity change.

I have a few ideas for exploring that, and for looking into attrition rates more generally, but they aren’t fully formed yet. For now, I’ll settle for saying this: fastballs keep getting faster, but there’s no evidence that the velocity increase is due to returning starters adding velocity. Anecdata notwithstanding, if you’re looking for why everyone throws 95 now, I think you need to look for what happens before pitchers reach the majors, not what happens after they’ve arrived.





Ben is a writer at FanGraphs. He can be found on Twitter @_Ben_Clemens.

33 Comments
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sadtrombonemember
3 months ago

I have a different interpretation of this data. Pitchers should lose velocity year-over-year, collectively. And they do, every single year. It would take an enormous amount of velocity gainers to counteract the velocity losers completely. The fact that this year they lost less is noteworthy to me.

Of course, even so that could just be because it’s early in the year and things will return to “normal” later.

eph1970member
3 months ago
Reply to  sadtrombone

Should a 26-year-old lose velocity? I buy that for an older pitcher. But you are really arguing that Ben should be using regression analysis to control for age and year. That doesn’t solve everything, unfortunately. There’s likely to be statistical bias, as pitchers who have lost velocity may get cut or may retire (as Ben noted). I’d read that article, but would anybody who is not an economist?

Dmjn53
3 months ago
Reply to  eph1970

I would also argue there a hell of a lot more younger pitchers right now than there are guys old enough to be losing velocity

Lanidrac
3 months ago
Reply to  Dmjn53

Even so, you’d expect that the younger guys would generally maintain their velocity, so even the smaller amount of older pitchers who don’t get cut or retire should still push the overall numbers in a significantly negative direction if we weren’t seeing an unusual rise in velocity in many younger pitchers.

sadtrombonemember
3 months ago
Reply to  eph1970

On average, I would guess that it would be more pronounced at later ages than younger ones. But in general, I would guess the arrow is pointing down everywhere. Maybe for guys who are 24-26 it would be flat. Maybe. No, probably not.

Since Ben is looking at within person change I don’t think controlling for age and year is right. Stratifying by age group should do it, unless it’s just slicing it so it’s so small the noise is too much. But I doubt there would be any group that on average is going to gain velocity on a regular basis.

I think the difference I have is not one of analysis or interpretation. What do you think would happen in a normal year? I think that assuming that there is no change in a normal year doesn’t make sense and that the analysis bears it out.

Last edited 3 months ago by sadtrombone
uptheirons
3 months ago
Reply to  eph1970

Yes. Muscle strength peaks at 25. http://www.sportsci.org/encyc/agingex/agingex.html

tung_twista
3 months ago
Reply to  sadtrombone

>The fact that this year they lost less is noteworthy to me.

Is it? 
There are 14 years of data and this year is tied for 4th smallest velocity deduction.
4th-5th out of 14 is not very noteworthy in my opinion.
You would have had a much stronger case saying that there is something going on with starters showing significant loss of velo in 2017-2018. 
The two most extreme changes in the past ten years consecutively happening doesn’t sound like coincidence, does it?
Yet, if you expected the trend to continue, you would have been wrong. 

Sometimes, noise is just noise.
That is why I really appreciate Ben’s articles showing “null” results like this.

dl80member
3 months ago
Reply to  tung_twista

Some of that was likely the ball changing. The seams were lower, which led to less spin and also less drag

sadtrombonemember
3 months ago
Reply to  tung_twista

I think you almost convinced me. Almost.

mgeoffriau
3 months ago
Reply to  sadtrombone

When you say that pitchers should collectively lose velo year-over-year, do you specifically mean a discrete group of specific pitchers? At first I thought you meant “all pitcher” which would also include new pitchers joining the majors (and excluding pitchers leaving the majors), which I would guess is the primary mechanism by which the “all pitchers” velo doesn’t drop year-over-year.

sadtrombonemember
3 months ago
Reply to  mgeoffriau

As a group, pitchers should collectively lose velocity. Whether that’s due to age, wear and tear, or some combination of the two, the overall trend should be down. Plenty of players should add velocity, it’s just that it should be outweighed by it going down. (2021 was weird, though.)

mgeoffriau
3 months ago
Reply to  sadtrombone

But only when considering returning pitchers, yes?

sadtrombonemember
3 months ago
Reply to  mgeoffriau

Yes, that’s right.

channelclemente
3 months ago
Reply to  sadtrombone

Charlie Morton didn’t get the email.