Should Paul Goldschmidt Avoid the Home Run Derby?

Paul Goldschmidt has already indicated that if he were invited to participate in this year’s Home Run Derby, he would say he wasn’t interested. But would it hurt Goldy’s swing if he did participate, given that he’s an all-fields hitter?

I don’t want to put words in Goldy’s mouth — in my opinion, when this story “broke” yesterday, everyone was adding to what Goldy said to help him make his point. Let’s let Goldy speak for himself. From the mlb.com article:

“You guys see me hit out there, it’s not something I’m doing during batting practice,” said Goldschmidt, who focuses on using the whole field.
Goldschmidt entered Tuesday’s action with 15 homers, sixth-most in the NL. The Derby participants for the NL will be selected by Rockies shortstop Troy Tulowitzki.
“I don’t think I’d do very well if I did try,” Goldschmidt said of trying to hit home runs. “So it’s not something if they asked that I’d be interested in doing.”

Note that the “focuses on using the whole field” part was not said by Goldschmidt. I read this and thought Goldy was saying that he probably wouldn’t be a very entertaining participant, because he’s never just practiced to hit home runs, and he couldn’t step in at the Derby and just pretend it was batting practice. Maybe it’s not so much that he couldn’t do it — if memory serves, Ichiro Suzuki once won a derby in spring training — but more that he’s not a good “fit” for it. Which was, by the way, the word choice in the title of the mlb.com article. All good.

I looked for some feedback on the twitter last night about whether Goldy should participate. To my tweet, there were more replies like this:

@InsidetheZona he shouldn’t be involved. He is a pure hitter. Would mess up his swing going for homers he made right choice

— Miggy (@miggyg08) June 25, 2014

Than like this:

@InsidetheZona After Upton got screwed out of going in 2011 I’d like to see it. Lost year anyway, so at least some short term entertainment. — Joe B (@JoeCB91) June 25, 2014

There is definitely evidence to suggest that hitters fare worse after participating in the Derby. But there’s a huge lurking variable there: hitters selected for the Derby are likely to have hit a whole bunch of dingers in the first half. And hitters who have hit a whole bunch of dingers in the first half are likely to be outperforming their true talent level. And players outperforming their true talent level in the first half are more likely to regress in the second half.

To put it differently: if you named the entire Home Run Derby squad, but then the Derby never actually happened, we’d still expect that group of eight players to fare worse in the second half. That’s just the nature of the beast. And it also makes it hard to draw conclusions about just how harmful the Derby might be to any particular player’s hitting. It’s just the nature of the beast.

Nonetheless, we can still compare hitters to other hitters. And in a fun small sample exercise, I looked at all 24 hitter/seasons from the last three years of players who participated in the Derby. I like weighted on base average for this type of thing — it weights each hitting event like home runs, singles, walks etc. appropriately based on the exact extent to which they matter to scoring runs (with a coefficient to make it look similar to OBP). The group’s first half wOBA was .394, and in the second half they put up a .355 wOBA. That’s an average drop of .039 points in wOBA, which is pretty enormous. For reference’s sake, that’s almost enough to turn Goldy into a hitter like Aaron Hill last season, or Miguel Montero this season. You can see why one measly home run hitting competition doesn’t seem like an adequate explanation.

But some guys dropped more than others, and I wanted to see whether that drop correlated with the extent to which these players were spraying balls to all fields. To determine the latter, I looked at career batted ball data as a way of getting a good general sense of whether they were pull hitters. On average, the group pulled the ball 41.0% of the time, hit it up the middle 34.3% of the time, and hit it to the opposite field 24.6% of the time.

Here’s the thing: there was a significant correlation between pull percentage and first half/second half drop in wOBA: .511 (1 being perfect lockstep, 0 being no relationship, and -1 being a perfect inverse relationship). That’s a stronger relationship than HR from season to season, even. But it went in the opposite direction of the expected result: the more you pull the ball, the more likely you are to see a drop in production after participating in the Home Run Derby.

Why? I have no idea. Maybe hitters who use all fields have better bat control anyway, a better feel for their swing — and maybe those guys are able to adapt (and adapt back) better than their pull-happy friends.

But the most pull-happy of Derby participants in the last three years had the biggest drops in production. Mark Trumbo‘s Pull% is an amazing 50.1%, and in the year he participated in the Derby, his wOBA dropped .129 points (!!!) from first half to second. The highest Pull% in the group is actually Carlos Beltran‘s 50.6%, but his wOBA also dropped significantly: .075. The next-highest Pull% is Jose Bautista‘s, and his wOBA dropped in both years (.089 in 2012, .100 in 2011). And, for context: a 100-point wOBA drop is like turning Goldy into Cliff Pennington.

And so what about Goldy? Paul Goldschmidt hits the ball to his pull field just 38.4% of the time, which is pretty remarkable. And that is one of the lower pull percentages of the group, although there’s a cluster of players right around 38% (Prince Fielder, David Wright, Robinson Cano), and Matt Holliday (35.2%) and Bryce Harper (32.2%) have pulled the ball less frequently. Average up those eight player-seasons, and you get a wOBA drop of…

Not a drop at all. Combining the Fielder, Cano, Holliday and Harper seasons, we get an average increase in wOBA of .007 points. Not much, but that’s kind of the point, right?

Maybe Paul Goldschmidt shouldn’t participate in the Home Run Derby. But recent evidence, using Pull%, suggests that if he did, he’d come out of it just fine.