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Matt Kemp's 2010: A Statistical And Mechanical Analysis



As some of you already know, I did an analysis on Matt Kemp's struggles at the back end of August in 2010, but I wanted to revisit that analysis now that the season is over and everything has settled.

Obviously, a lot of the points I cover in this post will be rehashed from before, but I wanted to make my True Blue LA debut with analysis that is as complete and thorough as possible.  At least that way I can leave a good first impression before you watch me devolve into a temperamental ranting lunatic.

Until that day comes though, enjoy my analysis of Matt Kemp's 2010, as I certainly enjoyed doing it.


Matt Kemp struggled in 2010, there's no real way around that.  However, perhaps even more relevant to the discussion, he fell well below the expectations of fans, which in turn generated a greater than normal backlash against him.

Journalists and bloggers alike used many words opining about Kemp last year, whether it was defending him or condemning him.  Many of them have attempted to analyze why his struggles came so suddenly, and I think their opinions, for the most part, took the lowest common denominator of analysis and ran with it.  That is, they speculated and inferred on mental focus, effort, and other intangible factors that are not related to actual performance, largely in part because it's essentially impossible for anybody to prove that angle wrong.  It's one of the last frontiers for objective analysis, so many abused it in order to get their opinions across without being proven a sham.

Personally though, instead of endlessly speculating on his mentality, motivation, intelligence, and other factors that we can’t and never will know, I'm setting out with the intent to focus on why he struggled on the field, what he can do to fix his problems, and whether corrective measures have already been taken.


The idea for this post was formed in August of 2010 as I was thinking about the perception of Matt Kemp's season.

Contrary to the popular belief at the time, I didn't think Kemp's struggles could be attributed to his habitual chasing of low and away sliders.  In fact, I believed that he was as vulnerable to that pitch as he ever was.  Rather, I thought the actual problem with Kemp was that fact that he was getting himself into negative counts more frequently because he was swinging through and fouling off hittable fastballs that he didn't miss in 2009.

It was a feeling that I had gotten from just watching the games, and it was a hypothesis I wanted to explore further, thus this epic train of thought was born.

What's Luck Got To Do With It?

So what about my hypothesis?  Is it true?  Is it false?  I'll get back to that shortly, but I first have to know whether or not his season was adversely affected by luck, as that could subvert the whole premise of this analysis.

Looking at his season statistics, his BABIP was .295, which is about league average, but considering his previous seasons ended with BABIPs of .330, .411, .361, and .345, it's safe to say that it was far below his norm.

Of course, that doesn't prove that he has been unlucky, as he could be hitting more routine pop-ups or something.

Since hitters can influence their BABIP through the types of balls they hit, tools like xBABIP became a necessity, as it accounts for both batted ball type and park factor.

When you run through those calculations, it shows that Kemp's xBABIP should have been around .335, which likely indicates that he's been more than a tad unfortunate.

Giving him a BABIP of .335 would result in 16 more hits, which would include 3 more doubles, 1 more triple, and 3 more homers.  All of a sudden, his line becomes .276/.334/.500/.834.

Still below expectations? Absolutely. Panic worthy to the point of scapegoating him and having eleventy billion articles written about him? No chance.

Still though, even giving him the benefit of the doubt, it's clear that he struggled in 2010 when compared to 2009, but why?

You Think You Know But You Have No Idea

I've noticed that there are three main statistic based arguments for Kemp's struggles that I believe are incorrect.

He lacks patience.

Lots was been made about his supposed lack of patience, but Kemp actually set a career high in walk rate, and it’s on a four year incline (5.1%/7.0%/7.8%/7.9%).  Additionally, he saw 3.96 pitches per plate appearance, which was exactly the same as last year.  In actuality, I think there's a better case to be made that he was being too patient by taking pitches and getting behind in the count early.

His BABIP is dropping because he no longer hits the ball as well.

Kemp’s BABIP is indeed on a four year downturn (.411/.361/.345/.295), but I think there’s a rational explanation for it. Over those same four years, his xBABIP has been .325, .353, .338, and .335. So basically, Kemp was extremely lucky in 2007, deserved what was coming to him in 2008 and 2009, and was unfortunate in 2010. No big mystery to solve there, in my opinion.

Furthermore, the xBABIP drop from 2008 to 2009/2010 can be explained by his concerted effort to hit more fly balls. His ground ball rate over that time span was 45.0%, 40.4%, and 40.7%, while his fly ball rate was 32.0%, 38.3%, and 39.3%. Since fly balls are converted into outs more often than ground balls, it goes to reason that a slight drop in xBABIP would come along with it. Of course, the advantage of more fly balls is more home runs, and Kemp has continued to hit for more power, as his HR/FB rate is on a three year upswing (12.3%/14.4%/16.2%).

His BABIP is dropping because he's slower than before.

This is a generally subjective measurement, and while it’s certainly a possibility, it’s difficult for anybody to tell for sure by watching the game, and it's almost impossible to prove.  Believe me when I say that, because I tried just a few days ago, but I found there was little video shot from behind the batter showing him running in real time through a close play at first base.

Regardless, even if we can't time him, three main pieces of evidence for this hypothesis surfaced: Kemp had 6.5% less infield hits in 2010 than in 2009, his defense suffered, and his basestealing was atrocious.

However, from 2007 to 2010, his IFH% has gone from 16.3% down to 6.3% up to 12.1% and now back down to 5.6%.  More than a trend, it seems to be random.  We also now know that advanced defensive metrics should be taken with a grain of salt, but I don't think anybody is arguing that his defense wasn't worse than in 2009.  However, it's just as likely that his issues weren't speed related, but rather his jumps were what caused the regression.  The same explanation can be applied to his baserunning as well.  After all, if speed and athleticism was all that was required to be a good outfielder or basestealer, Joey Gathright would be the best defender and basestealer in the majors.

So What Is It Then, Genius?

Kemp struck out way too much.

Obvious answer, right?  Believe me, I know, but that's the cold hard truth.

After dropping his strikeout rate from 25.2% to 22.9% between 2008 and 2009, his strikeout rate in 2010 was 28.2%, which was well above his previous full season high.

I think everybody from casual fans to hardcore saberists can agree that Kemp's major malfunction is his propensity to strike out, but the cause of those strikeouts is what I'm looking to discover, and while there hasn't been much disagreement on the "what", there has been significant debate on the "why", and "how" it can be fixed.

Back To The Beginning

Now going back to my original hypothesis, I believe Matt Kemp’s contact struggles primarily stem from his inability to hit fastballs rather than curves and sliders.

Now, Albert Lyu over at Think Blue Crew (and now at FanGraphs) found that Kemp actually struggled against...well...everything.

There's a lot of information in the previous 16(!) plots, but here are the Cliff Notes version of what I found about Matt Kemp this season compared to last season:

1) Swinging at less pitches (more walks), but whiffing more on hittable pitches (more K's)
2) Making less contact, but when he does make contact, he also puts the ball in play less
3) Swinging at (and missing) more high fastballs from RHP, resulting in less contact
4) Whiffing on LHP fastballs down the middle of the plate, making more contact on high LHP fastballs and less on down the middle LHP fastballs
5) Swinging at more inside RHP breaking balls and making less contact down the middle
6) Chasing low inside LHP breaking balls more, whiffing a LOT more, and making less contact down the middle

While this might seem to be detrimental to my argument, I actually don't think it is.  Being able to make contact with breaking balls less often is a problem, but he never made great contact with them to begin with, and he certainly wasn't getting positive value from hitting them.  By contrast, consider that Kemp derives almost all of his hitting value from battering fastballs, so if he can't make contact with those types of pitches, it's a much larger problem, which is the crux of my position.

Specifically, in 2009, he was worth 23.0 runs above average against fastballs, but -4.3 runs above average against off-speed pitches.  In 2010, he was worth 5.7 runs above average against fastballs, but -5.3 runs above average against off-speed pitches.  So yes, he did struggle marginally more against off-speed stuff, but the real problem was obviously the cratering of his production against the hard stuff.

Exploring further, Lyu's most recent research over at FanGraphs shows a specific type of fastball that Kemp suffers against in particular.


The lines represent the top (right on the graph) and bottom (left) of the rulebook strike zone while the grey line shows the league average. In 2009, Kemp whiffed on slightly more fastballs than the average hitter no matter the pitch height. But in 2010, Kemp swung and missed at many more fastballs, particularly high fastballs in the zone.


This shows how the 2009 Kemp made what appears to be more solid contact on high fastballs in the zone while maintaining a league average contact percentage on down-the-middle and low fastballs. However, the 2010 Kemp dropped below average in making contact against fastballs that were located within the strike zone.

So it looks like Kemp has not been able to catch up with high fastballs, the type of pitches he used to crush before. I was curious to see how Kemp performed differently based on a fastball’s speed. Here’s Kemp’s swinging strike percentage against fastball speed:


95+ mph fastballs resulted in similar whiffing behavior, but Kemp’s whiffs against lower-90s fastballs dramatically increased in the past year, nearly doubling that of the average hitter. It’s not that Kemp is missing a lot of plus-plus heat — he’s consistently whiffed on 20% of 98 mph fastballs throughout his career. He’s missing average fastball speeds as well. Finally, let’s look at Kemp’s contact percentage against fastball speed:


Similarly, Kemp’s contact percentage curve is completely submerged below both his 2009 contact percentage curve and the league average curve. He’s actually made less contact on 90-92 mph fastballs than on mid-90s fastballs, though I wouldn’t read too much into that without knowing the sample by pitch speed.

So specifically, he's having trouble with fastballs up, and that has been especially detrimental to his production.  The fact that velocity has little to do with his struggles gives credence to the possibility that it's his swing path that's the problem, not his ability to swing the bat itself.

Mechanically Speaking

As far as subjective analysis goes, instead of doing what a lot of other writers have done, which is speculate on intangibles, I'm going to take the path of looking at his swing mechanics and how they may have caused him to struggle.

Admittedly, this is a subjective exploration.  In no way is this the be-all, end-all analysis of Matt Kemp's mechanics or problems, but I do think it's exponentially more credible and useful than calling him lazy and dumb.

Through watching video, I discovered a lot of the minor issues that I have already mentioned in passing throughout this article.  However, there was one major malfunction that I felt was the catalyst for his mechanical problems.

Why Is This Even Important?

You'll see what I mean soon, but basically, striding forward on a consistent plane allows the hitter to keep his weight back, keep his hips closed, and keep his timing regular. The actual end alignment of the feet plays into the cause, but the important thing to note is what happens when Kemp's hips begin to drift away from the ball as he tries to start his swing.

When he prematurely releases his hips through his stride action, his bat dips further under the contact zone than intended in order to compensate for left side pulling away, and the bat head will be slower to get to the launch position because the core is the primary mover in bat speed. So by Kemp not having his stride in gear, instead of keeping his weight back, power stored, and remaining on time, he's off-balance, drained of bat speed, and late on pitches.

How Things Used To Be

The GIFs from this section are from around July of 2009.  They were taken from that month because it was the time in which he showed the most patience at the plate and was arguably at his best.

*There Used To Be Awesomeness Here*

In the fourth frame, Kemp picks his front leg straight up and strides towards the pitcher.  In the eleventh frame, his stride foot comes down in a direct line with his back foot.

As a result, his hips are closed and ready to be fired, and he puts them to good use by stroking a double to right.

*There Used To Be Awesomeness Here*

In the sixth frame, Kemp takes his stride foot straight up and moves it towards the pitcher.  In the twelfth frame, his foot comes down directly in line with his back foot, so his stride remains in tact.

Of course, he chases a horrid pitcher down and away, but the point of this is to show that no matter what the outcome of the swing was last year, he still had a consistent stride working.

*There Used To Be Awesomeness Here*

In the third and sixth frames, Kemp has his correct stride and plant working.

The point of this is to show that he had the same stride working even when he pulls the ball.

Where Did It All Go Wrong?

Now that I have established what his stride looked like last year, I am going to use it to compare and contrast with what his stride looked like about one year later, around July of 2010.  Not coincidentally, it happens to have been his most impatient month in 2010.

*There Used To Be Awesomeness Here*

In the third frame, his leg kick is still similar to what it looked like a year ago.  However, in the fourth frame, his hips begin to drift away from the plate, and by the time the sixth frame hits, the result of his step is obvious.

There is now a pronounced bailing of his stride foot away from the plate, and the line I had been drawing across the heels of his feet no longer travel from left to right but now go in the opposite direction.

*There Used To Be Awesomeness Here*

In the third, fifth, and seventh frame, you can see him bailing, but this time as he takes a pitch.

This illustrates that it wasn't just an issue when he was swinging away, but it was more of a muscle memory issue with his stride.

*There Used To Be Awesomeness Here*

Kemp is still bailing with his front side, but this time he homers to right field.

Using this to show that even when the outcome was good, the problem still existed.  Even a blind squirrel finds a nut once in a while.

A Month Later...

Mechanical flaws are nothing new to baseball players, and they are constantly working to improve their swings, so I skipped ahead to August with hopes of finding corrective measures being put in place.

*There Used To Be Awesomeness Here*

As you can see, not much has changed, as the hips are still drifting.

*There Used To Be Awesomeness Here*

For this three pitch sequence against Ubaldo Jimenez, we can see that while he is still pulling away, there is evidence of adjustments being made, especially when he takes the pitch.

In retrospect, this looks to be the baby steps to an eventual mechanical adjustment.

And Yet I See No Changes (Just Kidding, I Do)

As you already know, Matt Kemp finished 2010 with a flurry of homers, so to complete my analysis I wanted to take a look and see if he made any adjustments that led to his success.

*There Used To Be Awesomeness Here*

As you can see, there's a big difference.  His stride foot is headed toward the pitcher more than toward the dugout, and when he lands, his hips are closed and ready to explode.

More than a sudden change, it was a gradual improvement that stemmed back to the end of August/beginning of September, which is usually how adjustments go.

Now He's Going To Be An All-Star, Right?!

Despite the promising signs and obvious adjustments that Matt Kemp made to his mechanics towards the end of 2010, nobody knows whether this will directly lead to success in 2011.  For all I know, he might revert back to bad habits, develop another flaw, or be stricken by a myriad of other reasons that players struggle.

What I do believe though, is that Matt Kemp was making clear adjustments, and by employing the same approach and progress he was making at the end of last year to this coming season, paired with a little better fortune, he has a good chance of putting a horrible year behind him.

It's an old and tired cliche, but baseball truly is a game of inches, and even the slightest of adjustments could help Matt Kemp's star get back on track.