February 22, 2013

Pitcher Profile

Aroldis Chapman

by Harry Pavlidis

Two weeks ago, we examined the progress of Johnny Cueto, whose development from raw talent to well-rounded pitcher has rightfully brought high expectations. Today, we turn our attention to another widely acclaimed Reds pitcher: Aroldis Chapman. 

Chapman is one of the most enticing figures in baseball today. Most fans got their first impression of the flamethrowing lefty in the 2009 World Baseball Classic, when, in a rare dud for the Cuban national team, he failed to escape the third inning of an outing against the eventual champion, Japan.

Chapman defected a few months after his poor showing on the world stage, embarking on a life-altering journey from Cuba to Cincinnati and leaving behind his family and friends to pursue a big-league career. With that chapter fading slowly into the past, Chapman is making another transition, one that could change his career. After a breakthrough season in the bullpen, during which he established himself as the Reds' closer, Chapman is now being stretched out and targeted for the starting rotation.

How well-suited is Chapman to starting? There's no definitive answer. Having a triple-digit fastball is a good thing, but questions about durability, focus, and the quality of his third pitch are tough to overcome.

For some thoughts on Chapman's focus—the mental part of the equation—we'll defer to Craig Fehrman's feature on the 24-year-old, which appears in the March issue of Cincinnati Magazine. Fehrman covers some off-the-field details that you may not have read before; I was interviewed for the piece and found the final product fascinating.

Fehrman also found some interesting trends in Chapman's 2012 on-field performance and asked me to take a closer look. In a nutshell, there were four streaks (two good, two bad) that Fehrman used to break up Chapman's season.

My reaction to the question was mixed, but the findings were interesting enough to merit discussion in the Chapman profile and some additional follow-up here. There's another quote from the article that is more intriguing—we'll get to that shortly.

“Selective endpoints are a classic danger in analysis,” Pavlidis says. “Still, some things did pop up.” When Chapman was at his best, during Streaks A and C, hitters would swing and miss at his fastball 40 percent of the time. “That’s insane,” Pavlidis says, “just crazy.” During Streaks B and D, however, that percentage fell into the 20s (though for relievers that’s still considered good). This pattern repeated with other arcane measures—Chapman’s ability to get ground balls with his fastball, the outcome of his two-strike sliders—and always switched with the various streaks. According to multiple forms of evidence, then, Chapman became a markedly different player during the two types of streak. “And that,” Pavlidis admits, “is really curious.”

The most noteworthy curiosities in the article are not the ones I have listed below, but we'll stick to the on-field stuff. A few notes on the “streaks”:

1. Roughly 80 percent of Chapman's season was comprised of good streaks.
2. We can take the numbers and say they describe what happened in the other 20 percent, but we shouldn't assign more weight to them than they deserve.
3. Chapman's fastball averaged 98.6 mph in the good streaks, 97.9 in the bad ones.
4. There were no differences in quality of opponent based on three metrics: in-play slugging rate (measure of power), whiff rate (misses per swing), and ground-ball rate (as a fraction of balls in play).
5. Chapman's overall whiff rate in the good streaks was 42.7 percent and “just” 27.3 percent in the rest of the season.
6. Chapman's ground-ball rate was 43 percent in the good streaks and just 18 percent in the rest of his season.

For the most part, Chapman was an absolutely dominant reliever. He missed bats at an elite level and induced a roughly league-average rate of ground balls. The rest of the time, he was an average bat-misser (for a relief pitcher) with an extreme fly-ball tendency.

A Third Pitch
To succeed as a starter in his second and third trips through lineups, Chapman will need to show hitters something other than his fastball and slider, which are all he's needed to blow through his mostly one-inning outings. It's hard to say how well he'll be able to do this, since we've hardly seen him do it to date. ESPN's Keith Law was also interviewed for the Cincinnati Magazine profile and provided a relevant scouting thumbnail.

Law calls Chapman’s fastball “electric” and praises his “wipeout slider." “And I’ve always thought his changeup is better than he gets credit for,” he says.

After extended digging, I found some Chapman changeups. Four, to be exact. Two were easy, low-hanging fruit from the 2009 WBC tree. The other two are dubious and were found only by carefully tracking Chapman's game-to-game PITCHf/x data.

You can see how tricky it is to find the 2012 changeups by examining the following charts. Each isolates Chapman's pitches against right-handed batters, the 2009 WBC on the left and the 2012 MLB season on the right. Obviously, we have more data for 2012.

To preempt the question, yes, the 2012 changeups could be backed-up sliders. They happen to be the two pitches with the most arm-side movement of all of the deliveries he made last season, but they are barely discernible from his slider cluster.

Here's the first one: 

April 11, 2012 versus David Freese (0-2 count)

The catcher reaching for this pitch makes me wonder if Chapman actually wanted its movement to go away from the batter. There is a similar catcher reaction on the second changeup, below, but it’s not as extreme.

September 2, 2012 versus Matt Downs (2-2 count)

Neither GIF provides a clear view of the catcher’s sign. Is it two fingers? Or is there a third finger, perhaps indicating a slider? Looks like we have something to watch for and argue about as Chapman auditions for a rotation job this spring.

Thanks to Ben Lindbergh for creating the GIFs.

Harry Pavlidis is an author of Baseball Prospectus. Follow @harrypav
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