Wednesday, August 18, 2010

What's Wrong With Jonathan Broxton?

Never mind that the Dodgers are 4th in the NL West and over 11 games behind the Padres. Jonathan Broxton, known early on as "The Ox," has lost his closer role due to three blown saves in July and August. He has been wild, uncharacteristically wild. While he's still striking out a ton at 11.4 per 9 IP, he has walked more batters than struck out since the All-Star Break, resulting in a post-All-Star 8.10 ERA and 2.10 WHIP.

Every pitch ends in five distinct outcomes: ball, called strike, foul, in play, and swinging strike. I wanted to take a month-by-month look at these five outcomes of Broxton's fastballs and sliders since 2007. If we take a look at the percentages that each outcome occurred by month, maybe we can glean some information about what's wrong with Broxton. But I realized that the sample size for each month got pretty small, so instead, let's take a look at the average velocity and result of Broxton's fastballs by two-month periods (October games included with August and September) since April/May 2007:

First of all, take note Broxton's fastball outcome breakdown is not the end-all, be-all of his troubles. Command issues and being hit hard can be separate things, as struggling with command could be due to injuries and the like while being hit hard could be the result of a high BABIP, just plain bad luck. Still, this information should tell us something about Broxton's recent struggles as well as the dominant months of his career. First thing to notice is that Broxton's average velocity is consistently down compared to recent years. His fastball was hovering around 95.6 MPH during the first two months of this season after consistently averaging above 97 MPH in the previous two seasons. It seems to have gotten worse as the season has gone on (and the walks and runs started piling up), and Broxton is averaging a flat 95 MPH in August. This is a significant loss of velocity for his standards of hitting 98 MPH on the gun consistently.

The second thing I notice is Broxton's swinging strike percentage vs. his ball percentage. It's particularly off so far in August, with Broxton throwing balls 55% of the time compared the 30-35% in previous two-month periods. His swinging strike percentage is low, as well as his foul ball percentage. Batters are actually making less contact off Broxton this month, but that is misleading due to the high number of balls he's been throwing outside the strikezone. Sure, Broxton has only allowed 9.1% of balls in play in August thus far, but compare this to the other period that he allowed less than 10% of pitches to be put in play, and you'll recall that during that period in April/May of 2009, Broxton had 39 K's in 20 IP with a 1.44 ERA and holding batters to a .096/.200/.145 line. This is very different from the 6.75 ERA and .259/.394/.426 line recently since the beginning of July. Broxton's high ball% on fastballs has allowed runners to get on base, and his loss in fastball velocity suggests that hitters are able to get more solid contact off his pitches when they do.

Let's look at the average velocity and % of outcomes of Broxton's sliders now:

Broxton throws about 2/3 less sliders than he throws fastballs, which decreases the two-month period sample sizes by a lot, returning the volatile results you see above. Still, it's plain to see that Broxton's slider velocity is also down, around 86-87 MPH rather than the norm of 88-89 MPH. This is concerning, because Broxton's slider is effective and fools hitters into swinging out of the zone when it has the most movement, and his decrease in speed might indicate that he's also lost movement. As a result, since June, Broxton's slider has resulted in swinging strikes only 15% of the time, compared to the usual 25-28% when he is on top of his game. It may be interesting to note that 30% of Broxton's sliders in August were put into play and only 5% were fouled off, but the sample size here only consists of 20 sliders, so take that with several grains of salt.

Finally, let's just take an overall look at the pitch locations and movements of Broxton's four-seam fastballs and sliders this year vs. previous years:
Lots to digest here and some interesting stuff going on. First of all, I'm definitely still in "experiment mode" with R plotting, as you can tell by the paint splatter all over the legend in the fastball location plot. Also still trying to figure out how to get hexbin plots on the same graph, in order to show a gradient color scale instead of just a blotch of singular-colored paint.

Aside from that, let's focus on the pitch movement plots instead of the pitch location plots (there are just too many pitches in the pitch location plots to glean any meaningful information from non-splits data except, maybe, that Broxton throws his slider low and away from right-handed hitters). The four-seam fastball movement plot is very very telling. I noted earlier that Broxton's velocity has decreased this season compared to previous seasons, and this plot shows that Broxton's fastballs are not moving as much as well. It's a pretty significant difference. If Broxton's loss in velocity can affect his "rising effect" movement on his fastball that much, it makes it that much easier for hitters to get around in time AND to make solid contact on this pitch.

The slider movement plot is similar. There is less vertical movement on the 2010 sliders (blue) than all of the other sliders from 2007 to 2009 but similar horizontal movement. It's clear to me that both Broxton's four-seam fastballs and sliders have been more ineffective this 2010 season than previous seasons, largely because of their loss in speed and hence movement. This resulted in the disparity we saw in swinging strike percentage this year and previous years, and is a precursor to the hard hits off Broxton. Along with the loss of control that Broxton has had this season, throwing more balls than ever before, this has resulted in Broxton's ineffectiveness this season (at least compared to the stellar campaigns of previous years).

Frankly, Broxton just hasn't been the same pitcher, and it's pretty blatantly showing up in both of his main pitches, his four-seamer and the slider (I didn't look at changeups because he doesn't throw that many). There are all sorts of reasons for why this has happened, and to be honest, I think it's on the coaches and pitching coach Rick Honeycutt to figure out what's wrong with Broxton's pitches. If there was an internal mechanics change from spring training or something, they have to recorrect it back if they want Broxton to be a top NL closer again. Maybe he's nursing an injury and Broxton and/or the Dodgers are hiding it. Sure, taking Broxton out of the closer role and putting him in the time-out chair might help him settle down, but fundamentally, Broxton has been a different pitcher as of late and needs to correct whatever it is that's wrong. I feel that these location and movement issues are what the Dodgers and the media should focus on, rather than his "makeup" or his "fear of Carlos Ruiz" or that "he isn't a winner" and "doesn't have what it takes" etc. etc. etc.



Great breakdown. The slider is a great weapon in Broxton's arsenal. He needs to use it more.He rely's to heavily on the fastball. Since the velocity on his fastball has decreased, batters have sat on it. It's killing him. He used to throw the fastball as if he were trying to break a wall, now he throws it like he trying to find better command. I wonder if he was ever told to take it down a notch.

Seth said...

Great article, man. I wrote something kinda similar about a month ago, but I haven't been able to mess around with r-plots like you have.

I'd like it if we could work together, would you mind emailing me? xcoughitup at gmail dot com


Well done. I've been wondering for weeks why everyones been able to get ahold (up the middle) of the fastball and it's because it's down and in relative to where it was (fouled up/out of play or missed altogether). Slow it down a little and rely on it a little to much and we see te results. Why is George so sherrible???


Great work. I was curious if anyone had any thoughts on this. It looks like Broxton's velocity on his FB and Sliders this year is comparable to the '07 campaign which was still very good year. Even within this '10 season, Broxton has been two different pitchers (1st good vs 2nd half terrible) even though the velocity has been down all season as compared to '09 and '08. Even at 95mph, Broxton should be getting major league hitters out if he has command/control. He's done it before.

Looking at the last two months, I think Broxton has lost command/control of his FB and he knows it as evidenced by his increased slider usage. He's getting less strikes with the FB so he's using the slider more.

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