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Friday, July 25, 2014

The New Aroldis Chapman

The Reds' worst-kept secret is how amazing Aroldis Chapman has been this year, and the story of what he is doing differently to become so dominant.  Chapman is arguably in the midst of the best season of his career:
(sorry about the size of that one--click to make it bigger).

I know he had the 1.51 ERA is 2012.  But his strikeouts are at to 2 k/inning (18 k/9) on the season, his walks are stable, and he's allowed just one home run on the year.  He's been ridiculous***.

***This calls for a graph dump!

So how has he done it?  Well, part of it is that his velocity is up about two mph this year after averaging "just" 98 or so the prior three years.  Here's Brooks' Baseball's graph of that:
Aroldis has had months in which he has averaged over 100 mph.  But he's never had three consecutive months like this before in terms of sheer power.

The other thing that appears on this graph, of course, is that Aroldis is throwing his change-up again for the first time since 2010.  Here's a look at all of his games on the year in my favorite plot for identifying pitches:
It's pretty straightforward.  Chapman throws crazy-hard, with a fastball that breaks back away from a right-handed hitter while traveling at roughly the speed of sound.  And on top of that, he has a change-up that breaks almost 10 inches away from a righty, and then a slider that breaks in toward the right-handed batter's back foot.  The change-up and slider break opposite directions and travel roughly the same velocity.

Chapman is throwing both of his secondary offerings much more often this year:
After living almost exclusively with this fastball at times from 2011-2013, he's dropped his usage of that pitch into the high 60% range.  Instead, he's now throwing a quarter of his pitches as sliders, and is working in change-ups at a consistent, low rate.

The change-up has been very effective for him:
When he first started throwing it in May after coming back from the DL, batters had no idea what to do with it, and were swinging and missing 50% of the time he threw it.  They've since learned to lay off it (because they can't hit it: the pitch has a 95% whiff rate when they do swing on the season!!), and so we're seeing that whiff rate decline.  But, concurrently, we're seeing a spike in his fastball whiff rate.  So far in July, his fastball has induced the highest percentage of strikeouts of any month in his career.  It's correlational, but it sure looks like the use of his change-up has strengthened the impact of his fastball.  'Cause the fastball wasn't already an amazing pitch....

One last thing: on a recent Redleg Nation Radio, Bill Lack asked whether Aroldis gets beat more often when pitching down in the zone than when pitching up in the zone.  Here is are opposing batters' slugging percentages against Chapman in different parts of the zone.

First, left-handed batters:
(also known as "good luck, fella").  Lefties have gotten good wood on the ball when throws in the strike zone down and away, but otherwise are basically hopeless against him.

Now, right-handed batters:

Bill's perceptions hold true here.  When Chapman is throwing in the bottom half of the zone against righties, he's actually been hit pretty well during his career.  When he elevates the ball, however, it's been pretty much lights out.  And this isn't the pattern you always see either.  Here's a link to Cueto's graph; he gets it up in the top part of the zone as well.

Chapman seems to have noticed.  This year, he's throwing up in the zone more than in prior years, especially with his fastball:

All of Chapman's success this year is made all the more amazing by the fact that he suffered a serious head injury in spring training.  He's been one of the bright spots on the team thus far.  I don't know if he'll still be on the team by the end of the year, as he would seem to be a nice trade chip if Jocketty decides the Reds need to sell off some parts.  I think someone would overpay for him.  But it's fun to enjoy him while he's still a member of the Reds.

All graphs courtesy of the amazing Brooks Baseball.