Last week, I examined a list of hitters who were near the top of the league in exit velocity, while also lagging behind their peers in terms of expected results on their batted balls. For reference, I showed the following chart to explain how batters have performed during 2017 (updated for current games over the past week):
|z-score||Avg xOBA||Avg EV|
Average EV = 87.28
Variance = 7.12
Std Dev = 2.67
I didn’t do well at explaining this chart, last week. To reiterate, at the footer of the table you can see see that there are currently 395 players with over 30 balls in play in 2017. The numbers shown in each z-score row, display the average metrics for all players with exit velocities in excess of that performance level. For example, those with an exit velocity z-score in excess of 2 have average an exit velocity of 93.96, with an expected OBA of .406 (on same scale as wOBA). Please let me know if any confusion surrounds this chart.
Specifically, I wanted to take a stab at answering the question “are there hitters with elite exit velocity who are not capitalizing on it?” and mentioned Yandy Diaz as a potential candidate. A mea culpa, this is not meant to say that a player currently displaying elite exit velocity can change his swing to increase loft, and maintain the same exit velocity he is currently displaying. He may be able to. He may not be able to. What I am trying to look at is players who have shown that they posses elite exit velocity as things currently stand, while having a less than ideal launch angle. Does that predict that they can make a change and the results will be positive? No. However, it may indicate that a potential change could be considered.
Today, I want to look at more name brand option than Yandy Diaz, in Joc Pederson, who is expected to begin his rehab assignment Friday. For reference, here is the group of players with average exit velocities in excess of one and a half standard deviations from the mean.
|J. D. Martinez||0.535||168.3||16.50%||15.30%||18.80%||22.40%||95.1||13.7||3.2|
Average EV = 93.01
Average xOBA= .391
Like I mentioned last week, that’s some pretty elite company. While hitting the ball hard does not guarantee success, as we see based on a couple of names on the list, it is the apparent best thing a player can do in order to increase their expected results when making contact.
So why hasn’t Pederson been able to capitalize on the exit velocity he has possesses? The issue is much the same as Diaz. A very small portion of the batted balls he is hitting are at launch angles that would make the contact valuable. To phrase it another way, he hits the ball hard. However, the ball isn’t hit at a launch angle that allows the elite exit velocity to be as valuable as it would otherwise be. We know that balls hit under zero degrees, and over thirty nine degrees are the least valuable batted balls, and this season, nearly 65 percent of his batted balls fallen into the above buckets.
While Pederson doesn’t have the exact same problem as Diaz, who is hitting zero balls in the air, he appears to have had a problem making valuable contact during 2017. While he should certainly regress based on career norms and that should work in his favor, it is clear that so far in 2017 his batted ball results pain a profile with which it is difficult to sustain success.
|Lg Avg EV||BIP||Avg EV||Vertical||Spray|
While Pederson displays well above exit average velocity, the problem he appears to be having stems from a combination of pop-ups and weakly hit ground balls (I say weakly hit, because, while exit velocity still his well above average on his balls hit below zero degrees, the launch angle is such that it is difficult for those balls ever to be valuable.) So the question becomes, is this a sample size issue? Is there anything in Pederson’s profile to suggest that this is a problem that is likely to continue, as opposed to just the lingering impact of his groin injury. Luckily, we now have minor league batted ball data here on Fangraphs, and can take a look at if Pederson has had an issue with pop-ups throughout his career. From this data, we can see that he has routinely run infield fly ball rates in excess of 15% throughout his minor league career. (I am using this as a corollary for pop-ups). While his ground ball rate in 2016 is a career high, it has been increasing since his debut, from 35% to around 40% to 49% this year. While he could certainly regress toward career averages, the upward trend isn’t ideal. Certainly a portion of this could be related to the injuries he has sustained this year.
So how does that impact him for fantasy leagues? Simply put, like Diaz, there is extreme cause for concern in his batted ball profile this season. This isn’t a case where his poor start is not supported by underlying skills. So, I’d proceed with trepidation. While he certainly isn’t doomed, he doesn’t look like the mid-tier outfielder he was drafted as in most leagues.
However, while he has made poor contact in 2017 (less than ideal launch angles), his exit velocity is not a cause for concern. To take an optimistic view, despite injury he doesn’t appear to be hitting the ball with less authority than prior years. Exit velocity is important. It’s more important than launch angle. However, you’re OPS is in the air, and Pederson could benefit from a change in line with this.
Joe works at a consulting firm in Pittsburgh. When he isn't working or studying for actuarial exams, he focuses on baseball. He also writes @thepointofpgh. Follow him on twitter @Ottoneutrades