Mandatory Credit: Josh D. Weiss-US PRESSWIRE

Jair Jurrjens and PitchFX Part II

Welcome back to my first insights and experiments with PitchFX and Jair Jurrjens. If you didn’t catch the first part of this series you can check that out right here.

In Part I we talked about the use of his pitches from 2010 to 2011 and took a quick glance at his whiff percentage for each pitch during the respective seasons. Today we are going to be looking at the sabermetric outcomes, as well as the speed and movement on his pitches.

Let’s jump right into it then:

the rest after the break…

Sabermetric Outcomes


Pitch Whiff/Swing GB/BIP LD/BIP FB/BIP
FA 19.14% 42.19% 18.75% 32.81%
SI 9.25% 39.78% 19.35% 33.33%
SL 38.69% 39.53% 18.60% 30.23%
CH 24.23% 39.08% 25.29% 28.74%


Pitch Whiff/Swing GB/BIP LD/BIP FB/BIP
FA 18.06% 34.25% 16.44% 40.41%
SI 8.67% 56.38% 13.83% 26.60%
SL 33.95% 30.68% 13.64% 51.14%
CH 13.77% 50.00% 17.11% 28.95%

The only good thing I can pull out of this data is that all of his pitches this year resulted in less line drives, which could be him locating pitches better or simply the luck he accrued in the first half of the season. Other than that nothing else looks good.

All of his pitches dropped off in whiff/swing% especially the change up which is getting us closer to finding out why his K/9 dropped so much. We need to check in on the speed and movement before we can really understand however.


Pitch Horizontal Movement Vertical Movement Speed (MPH)
FA -3.24 -13.72 92.05
SI -7.64 -15.90 91.47
SL 5.25 -32.33 81.20
CH -8.90 -23.99 84.19


Pitch Horizontal Movement Vertical Movement Speed (MPH)
FA -3.42 -14.94 89.81
SI -7.78 -17.30 89.52
SL 4.53 -32.78 79.69
CH -9.24 -22.80 83.99

From 2010 to 2011 Jurrjens lost 2.24 mph on his fastball, 1.95 mph on his sinker, and 1.51 mph on his slider. The changeup on the other hand was pretty much the same (.2 mph slower). All of this is basically your worst case scenario. You don’t wan to lose speed on any of your pitches but the changeup because the speed differential is what makes the pitch effective in the first place (hence the name changeup, as in “change up the speed”).

This is likely the reason the change up became so ineffective this season (13.77 whiff/swing % compared to 2010’s 24.23 whiff/swing %). A fastball more than 2 mph slower, plus the increased use of his slider, where probably the two reasons the changeup didn’t get as many whiffs as 2010. The speed differential in the fastball and the changeup during 2010 was 7.86 mph. In 2011 that differential shortened to 5.82.

The next thing we can talk about is the movement of JJ’s pitches. From 2010 to 2011 there isn’t a huge difference in horizontal movement or vertical movement. So it looks like the biggest impact on Jair Jurrjens has been the lack of velocity, like so many people have been saying. I just took a little while to get there.

This wraps up the mini series on JJ and PitchFX. If you have learned anything from this let me know, I would love to know if I am actually giving you guys some insight. I know I have improved my knowledge of pitching stats based on this little project. If you think I did a bad job, let me know what I can do better or what stats I didn’t use properly.

The UNC-Duke game is coming on so I’ve got to roll. Let’s go Heels! (I really hope they win because this is being published the morning after the game…)

Tags: Atlanta Braves Jair Jurrjens PitchFX

  • clearwall

    I guess what I glean from this info is that JJ is trying to become more like the Mad Dog than CC. Remember, Greg used to throw in the mid-90s as well, but after working with Leo he started throwing a MOVING fastball at around 88mph. I dont have a problem with lowering your velocity if it means you’re throwing more strikes and making the ball dance more often. Just like you said yesterday, the fact that he threw more sliders and sinkers last year kind of shows what he was trying to do, and by all data points before the ASG, it was really working well. I don’t see a problem with this at all. Id much rather see JJ throwing 88-90 with sinking movement and come back the next day with Hanson throwing 95 FB and his absolutely wicked curveball. That would really work out well for our series’.

  • leetro

    When I start writing here, I’ll be using for Pitch F/X numbers. It adjusts the vertical movement more based on velocity, since slower pitches have more “sink.” It doesn’t completely eliminate the skewness, but it does better than Brooks.

  • CarlosCollazo

    @leetro Gotcha. Yeah I would love to gain some PitchFX knowledge from you man. Can’t wait to read some of your work. I’ll check out texasleaguers in the meantime.

  • CarlosCollazo

    @Trey Peters I agree, but I don’t like how his velocity is going down already. It’s fine to take that approach when you start to age and Half to rely on movement and deception but he needs to have as much speed on his fastball as possible. If it’s not there he may as well try out a 2-seam or a cutter. The change up pretty much becomes useless when his fastball is around 88 however. Did you hear about Hanson getting his delivery a lot smoother? Sounds good, but I wonder how it will affect him.

  • aryanspecial

    @CarlosCollazo @Trey Peters Carlos, can’t say I agree with the change being ineffective when throwing 88. But I assume you mean his changeup currently. He needs to cut the velocity on his change for sure. But Glavine had a mean circle change and he didn’t throw too hard. So one thing I gather from this info is that Jair needs to work on his changeup more than anything to compliment his change in velocity. Coming off of a knee injury, I can’t expect his velocity to come back. So that’s what I would focus on.

  • CarlosCollazo

    @aryanspecial @Trey Yes, I mean his current change and current fastball. Also, in 2011 his changeup had lost more than an inch of vertical movement. That plus the speed made it a pretty weak offering. If he can slow it down or increase the movement I don’t see why it can’t be a solid pitch though.

  • clearwall

    @CarlosCollazo @Trey Peters

    Well, if you remember(and you might not only being 17) but Maddux didn’t cut his FB as an aging decrepit old man. He did it the year after he won a Cy Young in ’92.

    But regardless, I’m of the belief like Leo was back in the day, that throwing heat on a straighter trajectory is worse than pulling back a little and making the ball move. Your research here proves that Jair is leaning more towards the latter which will a)prolong his career and b)allow him to be a more complete pitcher

  • CarlosCollazo

    @Trey Peters Unfortunately I was extremely young when Maddux was around. It is a tragedy and I wish I could have watched more of him.

    Personally, I would much rather hit against someone throwing a hard, flat fastball than a slower one with a lot of movement. I am not sure how much more/less movement Jurrjens has on his fastball but it would be interesting to see whether he does or not.

    Did Maddux change to 2-seam or just slow it down?

  • clearwall

    @CarlosCollazo See, I grew up on Maddux. I was 10 when he signed with the team and that’s about the time I really started watching sports and especially baseball. Next to Dave Justice, Greg was my favorite Brave ever.

    As far as what he threw, he pretty much invented the cut fastball.Now, I know Rivera really perfected it and made it a weapon but that’s because he only threw, what 3 pitches? Greg commanded EVERYTHING. 4-seam(which had wicked movement as well), 2-seam, slider, curve, change-up. Hell, he might have even thrown a few knucklers at some point. I wouldnt be surprised if he had. The guy could hit a teacup from 60′ 6″.

  • CarlosCollazo

    @Trey Peters Yeah one of my biggest regrets is being born in 1994. Strike year, too young to see the greatest rotation of all time. It’s a shame really. But I am excited for all of our young talent, they have the potential to be extremely good.