Jarrod Parker On Tommy John Surgery and Sliders

The ranking might change day-by-day, Jarrod Parker said, but he agreed: “Overall I would say the fastball and changeup are my two better pitches.” And that changeup is special — he threw it more than any secondary pitch last year, it was his best-rated pitch, and a big part of why he had the 21st-best swinging strike rate among qualified starters. It wasn’t always that way, though. Coming out of high school, Parker was a fastball/curve guy. So what happened?

“I got hurt and didn’t want to throw as many breaking pitches, so I started working on a changeup.”

Maybe that doesn’t seem like a big deal to some, but I’ve been interested in this for a while. Some flawed research of mine once provided preliminary findings that high-slider pitchers like Brett Anderson were prone to injury, and then Jeff Zimmerman followed with a more statistically robust approach that backed up the general finding that the slider and curve are tough on the elbow. The fact that a Tommy John survivor was now telling me that he didn’t want to throw those pitches as much after his surgery — that fact actually physically caused me to lean in to his physical space a bit, and Parker gave me a look as he reached for his cleats.

Has the link between sliders and injury ever been made to him in an explicit manner? “Yeah — when you come back, there’s a reason why they limit you to so many [breaking balls] per batter, per inning,” Parker said. After asking him if his pitching coaches were familiar with the research that suggested sliders and curves were tough on elbows, he nodded, agreeing, but perhaps not willing to get into too much detail about his past and present relationships with different coaching staffs.

There was a little more. Parker talked about fastball control, and throwing quality strikes with both of his fastballs. He said that despite this current blip, he throws the same bullpen every time out — “about the same exact ratio of pitches I throw in my warmups” — and that he likes to keep things on a routine. I asked him about first strike percentage, something I’ve found to be well-correlated with walk rate, but he said “baseball is a game of adjustments” and that just the other day, the Tigers were doing a lot of first-pitch swinging. He didn’t necessarily feel like the first pitch strike was what was missing right now.

But I knew I already had something I wanted to check out when I got in front of a computer. Did pitchers coming back from Tommy John surgery use the slider less?

It’s a tough thing to really nail, since the PITCHf/x era only started in 2002 and your pool of Tommy John survivors with significant pre- and post- surgery PITCHf/x information is not large. The classifications themselves have changed slowly over the years, which might obscure real changes. And then there’s the simple fact that pitchers change and don’t change primarily based on performance issues. If you’re a reliever with a great slider, you may limit the sliders as you rehab, but when it’s time to get batters out in the bigs, you’re probably headed back to your best pitch to get the strikeout.

All of that said, it’s possible there’s some evidence that pitchers returning from Tommy John surgery use the slider less often.

The larger sample, which includes relievers and starters — 57 pitchers in all — shows a slight effect. Thanks to Brian Cartwright, who queried the PITCHf/x pitch types of this group in two classifications (a year before the surgery to two years after the surgery date), we can see that the slider is the only pitch that was used less often by the group when they came back from surgery:

Slider Cutter Curve Change Splitter
Average Difference, Post-Surgery -0.004 0.051 0.017 0.010 0.086

Already you can see a problem or two. The cutter usage leaps forward, so this could all be due to the change in classifications. Then again, since 2004, the overall slider percentage in baseball has stayed steady around 14-15%. In the end, the fact that 24 of the 47 pitchers that used sliders before and after surgery used the slider less is not a robust finding.

Limit it to starters, though, and it gets a little more interesting. And it does make sense to limit it to starters — starters have more pitches, by definition, and therefore can better diversify if one of the pitches causes them elbow stress. Since we’re down to 24 pitchers now, let’s just show the full sample:

Brett Anderson SP -0.037 0.056 -0.019
Chris Capuano SP 0.068 0.007 -0.145
Matt Chico SP -0.043 -0.017 0.016
Jorge de la Rosa SP -0.049 -0.059 0.151
Rubby de la Rosa SP -0.065 -0.010 -0.026
Jaime Garcia SP 0.144 -0.385 -0.074 0.068
Shawn Hill SP -0.072 -0.057 0.178
Tim Hudson SP -0.077 0.084 0.046 0.018
Josh Johnson SP 0.008 0.047 0.080
Jesse Litsch SP -0.185 0.153 -0.092 -0.028
Shaun Marcum SP -0.051 0.021 0.035 0.038
Daisuke Matsuzaka SP -0.091 0.076 0.064 -0.006 0.021
Kris Medlen SP 0.052 -0.040
Sergio Mitre SP 0.020 0.049 -0.110
Jamie Moyer SP -0.011 -0.021 0.022 0.097
Russ Ortiz SP -0.147 0.234 0.088 0.008
Mike Pelfrey SP -0.054 0.023 -0.040
Ben Sheets SP -0.006 0.146
Stephen Strasburg SP -0.063 -0.003
Edinson Volquez SP -0.002 0.104 -0.056
Adam Wainwright SP -0.024 0.105 0.011 -0.013
Jake Westbrook SP 0.026 -0.009 0.041 -0.024 0.003
Jordan Zimmermann SP 0.069 0.009 -0.041
-0.029 0.029 0.012 0.006 0.031

Now the decrease in slider usage is more prominent. It could be erased by the increased cutter usage overall, but not once you look at it on a pitcher-by-pitcher basis. 14 of the 21 pitchers that used the slider before surgery used it less often after. If you discount any pitchers that showed opposite signs in their slider and cutter classifications, eight of 13 starting pitchers used the slider less after surgery.

The percentages aren’t huge. Parker lumped curveballs and sliders into one group, and we don’t see that sort of effect here for curves. But it does look like the conventional wisdom that Parker references — use the slider less during your Tommy John recovery in order to protect your elbow — underlines the sort of stress that snapping off a sharp slide piece can put on your ligaments.

Thanks to Jeff Zimmerman for his list of Tommy John surgery survivors, and Brian Cartwright for his querying skills.

Print This Post

Graphs: Baseball, Roto, Beer, brats (OK, no graphs for that...yet), repeat. Follow him on Twitter @enosarris.

Sort by:   newest | oldest | most voted
Jarrod Parker's Mother
Jarrod Parker's Mother
3 years 5 months ago


Mr Punch
Mr Punch
3 years 5 months ago

The definitions certainly have changed over time (though I don’t know about 2002-present). Decades ago, a slider (“nickel curve”) was basically what we now call a cutter – a fastball with break rather than a true breaking ball with the wrist and elbow action. What’s now called a slider was known as a slurve. (The lines have always been blurred, but they have clearly shifted.

3 years 5 months ago

Yes, but no, Mr. Punch. The slider and the cutter are actually executed differently as I under stand it. The cutter appears to be more a standard fastball grip but with offcenter pressure, whereas the slider grip is itself set up off-center. The distinction isn’t huge. Individul pitchers then and now, may have thrown a particular pitch identically and simply called it different things. More likely as I seem to recall looking back the decades, different players they threw the pitches differently but simply called them one thing, a slider.

The original slider, the ‘nickle curve’ as you say, did seem to have a much smaller break than our contemporary slider, I’ll agree there. In fact, I suspect that the early slider as thrown _would_ classify as a cutter nowadays. By that reasoning, there were no ‘slider’ sliders until the 1970s or so, when I recall pitchers beginning to throw the pitch with a sharp lateral break and getting raves when it worked. I think of Sparky Lyle and Guidry throwing wipeout sliders, though certainly other pitchers did also, but that was the time when it seemed to climp up the use and reputation charts as a strikeout pitch. If I was guessing, I’d say that pitchers exaaggerated the grip of the ‘nickle curve’ over time, trying for bigger break, effectively developing a new pitch with the same name, slider. It would be interesting to see some historical studies on slider terminology, mechanics, and usage, howeveer. This question of ‘is it bad for you’ has been around since sliders started ending careers in the 70s. Guidry’s elbow went to hell, for example.

I don’t recall the term ‘slurve’ even getting used until the late 1980s, though the players themselve may have had the term earlier. The slurve seemed to typically be a poorly commanded curve, with the resultingly dicey reputation, rather than an exaggeraged slider. But as always, some guys just got unusual breaks on their pitches due to hands, tension, mechanics, or the will of the gods.

Matthew Murphy
3 years 5 months ago

Might it make sense to only look at pitchers who were throwing a high (above average) percentage of breaking pitches before surgery? Know this makes a small sample even smaller, but I would think that those would be the pitchers who be cutting down on breaking pitches post-surgery.
For example, guys like Mitre and Capuano increased slider usage, but they were barely throwing it pre-surgery (2% for Mitre, 5% for Capuano) and were still well below average post-surgery.

Frank Q
Frank Q
3 years 5 months ago

As a baseball player I have used several different grips and “ways” of throwing both a curveball and slider. It has been explained to me that throwing breaking stuff in different ways can be more harmful depending on the hand position at release, grip of pitch, and arm slot. It would be impossible to break it down further by the first two of these categories, but I would be very curious as to whether there is a stronger correlation between TJ and high breaking ball usage from a 3/4’s arm slot or lower compared to the correlation between TJ and high breaking ball usage from a high 3/4’s arm slot or overhand.

3 years 5 months ago

What interests me *most* here is how limiting the number of breaking balls thrown actually changes tactical decisions and outcomes of the game. I can see some hazy, broad parallels between recent contact rules in the NFL that are already significantly changing how the game is played.

Given what looks to be a growing mountain of evidence on breaking balls::elbow health, what pitching skills are likely to be *more* valued in the future if in fact breaking balls will start to be rationed out more carefully?

3 years 5 months ago

“underlines the sort of stress that snapping off a sharp slide piece can put on your ligaments.”

watch the players who actually do this- try to snap off their sliders to get more bite and spin off towards first (RHP) or third (LHP) after they release it. then look at the ones who don’t.