The Evolution of Yoenis Cespedes

Tip: Click on any acronym to be taken to the Fangraphs glossary of terms. All charts/graphs are from the catcher’s perspective.

Yoenis Cespedes is a human cannon, and we all know his right arm is amazing.

However, when he’s not misplaying balls in the outfield to bait runners into trying for an additional base so he can throw them out, he’s an enigma at the plate. We sometimes see flashes of the player in the awesome showcase video, but we most often see a player with plate discipline issues who struggles with consistent production. After almost two and a half full seasons (not counting injuries), some strange trends have surfaced in the progression of Yoenis Cespedes as a hitter. With almost three months of baseball to draw from in 2014, we can now see some of the “adjustments” Cespedes has made this year.

The expectation in 2013 was for Cespedes to maintain the production of 2012 and possibly take another step. That didn’t happen.

Let’s remind ourselves what Cespedes did in his rookie campaign of 2012. Posting an OPS of .861, 23 home runs, and 16 stolen bases, he came in second in the Rookie of the Year voting, justifying the large contract Oakland signed him to. In most years, those stats would be good for first place, but most years don’t have Mike Trout as a fellow rookie. The expectation in 2013 was for Cespedes to maintain the production of 2012 and possibly take another step, building on the slightly improved plate discipline he showed in the latter half of the 2012 season (1st/2nd half BB% of 7.3/8.3%) to post better on-base numbers in keeping with the approach of the Oakland A’s.

Unfortunately, that didn’t happen. In 2013 compared to 2012, his OPS dropped 124 points, his strikeout rate increased 5% to 23.9%, and his walk rate went down to 6.5%. Here are his stats from both 2012 and 2013 so we can compare:

What happened? To begin, let’s factor in the good luck that Cespedes enjoyed in 2012. Some of the change in his performance from 2012 to 2013 can be attributed to his BABIP: in 2012, his batting average on balls in play was a gaudy .324, good for 27 points above the league average. In 2013, he not only regressed to the mean but also went below it, posting a .276 BABIP (league average was .297). Cespedes benefited from luck in his great rookie campaign of 2012, and was hindered by it in his comparatively poor 2013. However, it is also far too easy to point at BABIP and credit the statistic with largely explaining over or underperformance; Cespedes simply performed more poorly in 2013 than he did in 2012 outside of luck, and that shows most acutely in his strikeout and walk rates.

Jerry Brewer over at Athletics Nation broke down the meat and potatoes of both Cespedes’ swing mechanics and plate discipline in stunning detail early in the season, and they are incredibly descriptive of what Cespedes did well, and didn’t do so well, in 2012 and 2013. They should be prerequisite reading for truly understanding the background behind what we are discussing today: what Cespedes is doing so far in 2014.

First of all, let’s look at how pitchers attack him, and his swing rates on pitches in different areas of the strike zone, courtesy of Brooks Baseball. Since he came into the league, pitchers have attacked him from year to year like this:

As you can see, the pitching approach has been remarkably consistent, with little change between when he started in the league and the present. This approach is also understandable, as pitchers have tried to keep the ball down and away out of Cespedes’ power zone. As we’ll see in the next zonal breakdown, that’s a pretty effective way to pitch him, as he has a pretty high whiff rate on balls down and away. However, there was a particular hole in Cespedes’ swing that pitchers excelled at exploiting in 2013. Here is a comparison of his whiff rates between 2012-2014:

Besides having trouble with the pitch low and away, 2013 also features a pretty glaring weakness in pitches up in the zone. Diving deeper into the pitch types, as well as using the eye test on his at bats, it’s pretty easy to discern that the pitch he had the most trouble with in 2013 was the fastball up. Not only was he swinging and missing at pitches up and out of the zone, he was having trouble in general on pitches that were elevated, even if they were in the strike zone. Needless to say, this is an issue for a power hitter, as elevated pitches in the zone (not just fastballs) are pitches you look to drive.

You might also notice that 2013 has a lot more whiffs in general, no matter where the pitch was thrown, which presents us with an opportunity to look at Cespedes’ contact rates for the years in question. Here we have Cespedes’ contact and swing rates for pitches in the zone (Z-Contact%), pitches out of the zone (O-Contact%), and his overall contact rate:

This is where things start to get really interesting. We can obviously see that Cespedes’ O-Swing%, or the percentage of pitches outside of the strike zone that Cespdes swings at, has trended up slightly over the years, as has his Z-Swing and overall Swing%. Quickly, we can infer from this data some of the issues he had in 2013 that led to a downturn in his numbers. His Z-Contact% dropped over three points from 2012 to 2013, meaning he simply swung and missed on more pitches thrown in the zone. His Z-Contact rate for 2014 has stabilized with and actually improved over 2012’s mark to 87%, which is very close to league average.

However, what’s most interesting is that Cespedes has made better and better contact on pitches outside of the strike zone (his O-Contact%) over the three years he’s been in the league. This year has seen an increase in over 7% from 2013 – needless to say, this is quite a drastic change, and requires further analysis.

To do that, let’s bring in two really fun tools: a swing zone map and an interactive plot of all hits from Cespedes from 2012 to the present. The latter is part of the new Open Baseball project created by my good friend Adam Sax, and is part of a larger project aimed at mapping baseball data in simple, easy to understand graphics. Consider this the maiden voyage.

Below we have a swing zone map (from the catcher’s perspective) of Cespedes against RHP for the three years he’s been in the league, courtesy of Jeff Zimmerman at


Bringing together this graph, the whiff percentage charts and the contact rates supplied above, we can deduce a few things.

  1. Cespedes has limited his swing zone in 2014 on pitches up and out of the strike zone, which is the main pitch (the high fastball) he had trouble with in 2013.
  2. He has also narrowed his swing zone to almost pre-2013 levels on the outside of the plate, especially laying off pitches down and away.
  3. Finally, Cespedes has actually expanded his swing zone on both down-and-in and middle-in pitches compared to years past.

The first two are very positive, which is the reason why Cespdes has lowered his strikeout rate (19.2%) and increased his walk rate (7.5%) to nearly 2012 levels (18.9%, 8%).

But why would he expand his swing zone on both down-and-in and middle-in pitches? Shouldn’t that be detrimental?

To answer that question, let’s go to our interactive tool. Click around the graph below to see the locations (again, from the catcher’s perspective) of all of Cespedes’ hits from the past three years. These may not map exactly onto the previous strike zones we’ve looked at, but they give us generally a good idea of where events occur. Each year, hit type, and dot can be clicked on to provide the point during the game when it happened:

Let’s focus on the locations of the home runs from the past few seasons. Immediately, we can see where Cespedes’ power is: on pitches down and in. Looking at the distribution of singles and doubles, we can see a more even spread across the zone, with a slightly higher tendency toward hits on the inside part of the plate for 2012 and 2014.

Let’s tie all of this together. Cespedes has expanded his swing zone in the very places he hits for power, maximizing the number of pitches he can drive, whether in the strike zone or not. He has also decreased his swing zone on pitches off the plate outside and down and away, reducing his strikeouts, increasing his walks, and forcing pitchers to throw him more pitches in the zone. Finally, he is making much better overall contact this year, which could be attributed to many factors, like health, or simply getting better at hitting baseballs. One possible reason for the reduction in contact rates for 2013 is the wrist injury he carried for most of the season, but that is speculation. All that said, here we have his 2014 stats so far:

His counting stats for this year don’t yet fully reflect these improvements he’s made, but his peripherals do: a career high Line Drive rate (25%), Isolated Power average (.238), and extra base hit rate (11.7%). Given his BABIP, and these peripherals, I would expect his counting statistics to improve on their current marks.

We’ve seen how high rates of O-Contact% can have a negative impact on batted ball quality, increasing rates of ground balls and infield pop-ups. However, for Cespedes, it seems to instead represent an improvement in pitch recognition. At this point in his career, it’s fair to assume that he will never be a truly disciplined hitter, so we should now be interested to see whether this trend of choosing when and where to be successfully undisciplined will continue to pay dividends. It could simply be three months of data, or it could be the start of Cespedes knowing where his strength is, literally and figuratively.


Credits: Interactive strike zone chart courtesy of Adam Sax at Open Baseball. All other charts courtesy of Brooks Baseball/Jeff Zimmerman.

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