Participating in the Home Run Derby will not ruin Christian Yelich

Christian Yelich recently confirmed his participation in this year’s edition of the Home Run Derby, a development that wasn’t exactly surprising given that he leads all of baseball with 31 round-trippers.

As one would expect, the news was accompanied by claims from fans that taking part in the Derby will put an end to Yelich’s elite performance. The theory that focusing on hitting home runs for a night will have a negative effect on a player’s swing and production moving forward has been around for quite some time.

I’m going to say right off the bat that there’s really no reason to be worried about Yelich, who talked it over with hitting coach Andy Haines before making a decision and also called out a skeptical fan on Twitter after the news broke. The slugging outfielder reaffirmed on Thursday that he doesn’t believe the event will have any negative impact on his swing.

From a common sense standpoint, it’s hard to believe that one night will ruin a near-perfect swing that has helped Yelich achieve Bondsian levels of production for the past year-plus. If that were to happen, then his success was one massive fluke to begin with, which is simply not true.

In case you’re still not buying that logic nor the words straight out of the MVP’s mouth, let’s dig into the stats for answers.

We’ll start with last year’s Home Run Derby. Here’s what the data says about the participants as a whole before and after the event. wRC+ measures their overall offensive production while at-bats per home run zeroes in on their power production. (Something that should be noted is that while power is important, it’s not the only source of offensive value. A player could hit fewer home runs after the derby but be a more valuable hitter.)

wRC+ (Pre-Derby): 142
wRC+ (Post-Derby): 131

AB/HR (Pre-Derby): 15.9
AB/HR (Post-Derby): 18.4

The group as a whole did take a slight step back offensively after the derby, both in terms of overall production and power. However, they still combined to put up very strong offensive production the rest of the way, and they still hit home runs at a much greater frequency than the league-average 29.1 AB/HR in the second half. After the derby, the group as a whole went from being really good to... well, still really good.

Now let’s zero in on each of the individual participants from last year’s event. Obvious fact of the day: when someone is invited to the Home Run derby, it’s because they’re hitting at a high level, especially in the power department. However, not each participant is the same. There are established players who have been doing this for years. There are also players who have burst onto the scene thanks to apparent breakouts in the first half of the season. This year, we’ll even see contestants like Pete Alonso and Vladimir Guerrero Jr. who are currently in the midst of their debut seasons in the Majors. Because not every player has the same background or track record heading into the derby, I’ve included their career offensive numbers as part of the comparison.

The results vary for different players, which is to be expected. Bryce Harper took the trophy and went on a tear. Rhys Hoskins improved. Alex Bregman kept chugging along at the same high level he was on in the first half, legitimizing his breakout season. Javier Baez also saw his offensive production remain consistent with his first half. Max Muncy couldn’t keep up his unsustainable elite pace but was still an excellent hitter for the remainder of the season. Freddie Freeman saw his offense tumble a bit, but he was still 20% better than a league-average bat. Jesus Aguilar saw the most notable decline, but it looks more like he simply trended back to his career norms. Kyle Schwarber was the only participant whose offense fell below league-average. It’s entirely possible that competing in the event, especially through the final round, did affect him negatively, although it’s hard to tell for sure from a fan’s perspective.

Doing this exercise for just one derby doesn’t exactly prove much. What if we looked at every derby going back to, say, 2010? I’m not going to throw eight more tables into this piece, but the data can be viewed here.

There were 74 participants over these nine derbies (players who took part in multiple derbies were counted as a separate participant for each appearance). Here are the results regarding their power output:

• 77% were hitting home runs at a higher frequency than they had over their careers.
• 39% were hitting home runs at a notably higher frequency than they had over their careers (AB/HR of about 7 at-bats or more better than their career mark). In other words, they were clearly due for regression, regardless of whether or not they took part in the Home Run Derby. Of those participants, 34% of them saw their post-derby at bats per home runs end up close to their previous career average, while 17% saw it fall to a notably worse mark than their career average. The remaining hitters saw their home run frequency remain close to their first-half mark.
• Only 11 total contestants (just 14%) saw their AB/HR fall below the league-average in the second half.

Remember, power isn’t everything. Here are the results regarding the overall offensive performance of the participants:

• 71% were producing at a higher rate than their career wRC+.
• 60% had a wRC+ notably higher (about 20 or more points) than their previous career average, meaning there was a good chance that they would regress back toward their means. 68% of these players would go on to post a wRC+ about 20 points or more below their first half output after the derby. 22% of the 60% would limp to a sub-100 wRC+ after the Derby.
• 18% of the participants improved overall after participating in the derby (wRC+ of five points or higher post-derby)
• 12% of the participants were hitting for a 170 wRC+ or higher, which is unsustainably high for almost every player not named Mike Trout. Again, they were due to come down to earth regardless of their participation in the Home Run Derby. Most of them still put up excellent numbers for the remainder of the season, and none of them fell to a sub-100 wRC+ after the event. The “worst” qualified second half among these hitters was Matt Holliday’s 129 wRC+ in the second half of the 2011 season. That’s still Yasmani Grandal or Mike Moustakas level production.
• Only 17% (13 out of the 74 competitors) went from being above-average hitters before the derby to being below-average after it. It’s possible that the focus on hitting dingers had negative consequences on their swing mechanics, but there are also other factors (fatigue? nagging minor injury?) that could have been involved. For whatever reason, these players did struggle after participating in the Derby.
• The following players participated in multiple Home Run Derbies: Bryce Harper, Giancarlo Stanton, Robinson Cano, Carlos Gonzalez, Todd Frazier, Mark Trumbo, Prince Fielder, Josh Donaldson, Jose Bautista, Yoenis Cespedes, Matt Kemp, and Matt Holliday. Gonzalez’s performance tailed off significantly after both of his appearances, Frazier’s output sank to below league-average twice in his three go-rounds, and Trumbo struggled mightily after his first stab at the event. This leaves the door open for the possibility that these individuals saw their swing mechanics get thrown off by the derby. However, the remaining repeat contestants didn’t experience any overwhelmingly harmful effects.

What does this data tell us? There have been players who have struggled after participating in the Home Run Derby, so the theory that it messes with a player’s swing isn’t entirely baseless. However, it is way overblown. Automatically assuming that competing in the derby will ruin someone’s swing doesn’t fit with the historical evidence. The majority of players who see their performance drop are either regressing toward their career mean or predictably failing to maintain an otherworldly pace. Legitimate slumps (and in some cases, rather significant ones) after the derby have occurred, but they are much closer to the exception than the rule.

Now for the moment you’ve been waiting for: applying the data to specifically to Yelich. Yelich entered the year with a career wRC+ of 130. Since 2010, there have been two Home Run Derby participants with a career mark that high who have fallen to below-average offensive output after the event. Such a case applies to just 3% of all derby contestants in that span. The worst was Albert Pujols, who entered the 2015 season with a career 155 wRC+ and sagged to a 92 mark after the derby. That’s not exactly a comparable situation to Yelich’s, however, as we’re talking about past-his-prime Pujols, who was about to begin a decline from superstar to replacement-level player.

This season, Yelich has an absurd 180 wRC+, which is third-best among all MLB players. Since 2010, there have been zero derby participants who saw their output crash and burn from 80% better than league average to below average. Zero. None. The worst case was Matt Kemp in 2012, who posted a mind-blowing 208 wRC+ in an injury-shortened first half, then hit for a 116 wRC+ the rest of the way. Chris Davis, who played a full season in 2013, mashed his way to a 195 wRC+ in the first half, then produced a 129 mark after the derby, which is still very solid. Davis also entered the year with a 101 wRC+ for his career, much lower than Yelich’s career mark.

A single night’s worth of swings will not magically turn Yelich into a below-average hitter for the rest of the year. He’s not going to suddenly lose his power stroke. He won’t be a victim of a “Home Run Derby Curse.” The most likely outcome is that he’ll see his numbers “drop” from otherworldly to elite. If recent history is any indication, the worst-case scenario is Yelich goes from being Mike Trout to being a very good hitter.

Some hitters have struggled after participating in the Home Run Derby. Most often, it’s simply someone regressing toward their career norms. In some cases, a solid hitter has performed below league-average after the event. However, a hitter of Yelich’s caliber has very rarely experienced something like. The odds of Yelich encountering a true second-half slump and turning into a pumpkin specifically because he was in the Home Run Derby are about as close to zero as you can get.

When Yelich gets to take his cuts on Monday night, he’ll have his work cut out for him. He’ll be competing against the uber-talented Vladimir Guerrero Jr. in the first round in what figures to be a compelling matchup. Just sit back and enjoy the monster dingers that Christian Yelich will hit, then enjoy the monster dingers he’ll hit in the second half.

In the words of the man himself, “It will be fine, relax and have some fun.”

Statistics courtesy of FanGraphs.