The Early Trend of 2013: Dingers!

It’s April 10th. Most teams have played eight games out of 162, or about 5% of their season schedule. You know it’s early. I know it’s early. Data from a little over a week of baseball is highly suspect, which is why you’ll see things like Coco Crisp with an .829 slugging percentage or Vernon Wells with a 206 wRC+. Over these kinds of samples, any player can look great or horrible. Even at the team level, the numbers don’t tell you much of anything.

However, there is one set of numbers that stabilize very quickly – overall league averages. While the variance among players and teams is large, early season data at the league level is actually highly correlated with overall seasonal averages, for pretty much any major number you want to look at. For instance, here’s April 2012 data compared with 2012 overall data for many of the pitching metrics we look at regularly here on FanGraphs:

April 6042.2 8.2% 19.3% 10.5% 0.286 73.1% 3.84 3.98 4.09
Total 43355.1 8.0% 19.8% 11.3% 0.293 72.5% 4.01 4.01 4.01

HR/FB and BABIP were a little lower than the seasonal totals, but that’s normal, since April is the coolest month of the year, and the ball flies a bit better in the warmer summer months. Run scoring is usually lowest in April due to these factors, but beyond that minor adjustment, you can generally predict overall seasonal league run environment from April run environment with a pretty high degree of accuracy.

Since we’re only a little over a week into the season, we don’t have 6,000 innings of data yet. But, we do have 2,000 innings of data, and while they’re not as predictive as the full month will be, it is interesting to see how quickly these numbers have settled into something resembling a pretty normal overall league average line. Here’s that same chart as above, just for the first 116 games of 2013.

2013 2068.1 8.2% 20.2% 11.8% 0.289 72.0% 4.13 4.13 4.13

Walk rate is exactly where it was last year, and right in line with historical norms. Strikeout rate is up again, but it’s been aggressively trending upwards in recent years, and so that follows a pattern that we expected to continue. BABIP and LOB% look totally normal for this time of year. There are two numbers that are probably a bit higher than we would have expected, though, and they’re definitely related.

The league average ERA is 4.13 despite the increase in strikeouts for one simple reason; Major League teams have hit a lot of home runs in the first week of the season. Given the time of year we’re talking about, it’s almost an extraordinary amount of home runs.

During the 11 full seasons we have batted ball data from Baseball Info Solutions, HR/FB rate has never been higher than 11.3%, and that’s full season data. Here are the HR/FB rates for April over the last 11 years, along with that season’s total HR/FB rate and the gap between those numbers.

Year April HR/FB Season HR/FB Difference
2002 9.7% 10.7% 1.0%
2003 10.9% 11.2% 0.3%
2004 11.1% 10.9% -0.2%
2005 9.4% 10.6% 1.2%
2006 11.3% 10.8% -0.5%
2007 8.8% 9.6% 0.8%
2008 9.0% 10.1% 1.1%
2009 10.1% 10.1% 0.0%
2010 9.6% 9.4% -0.2%
2011 9.1% 9.7% 0.6%
2012 10.5% 11.3% 0.8%
Average 10.0% 10.4% 0.4%

Worth noting that April HR/FB rate has been higher than the season total in three of the 11 years we have batted ball data, so it’s not a hard and fast rule that HR/FB rate always increases throughout the summer. That said, it is true more often than not, and the overall average has put the increase at around half a percent. If teams kept hitting home runs at the same pace that they have so far, it would be the highest April HR/FB rate in the years that we have the data.

However, it gets even more interesting if we shift away from HR/FB and look at homers on contact. Since there’s a bit of a fine line between fly balls and line drives, HR/FB can be slightly affected by the categorization of balls hit in the air. If we really just want to look at a metric for measuring power, HR/CON is probably a better option.

I wrote about the HR/CON trend in baseball last summer, and noted that once you controlled for the rise in strikeouts, the rate of home runs last season was as high as it was during most of the “steroid era”. It didn’t quite reach the peak levels of the 1999-2001 stretch, but power definitely made a bit of a comeback last year.

It’s too early to call this a continuation of that trend, but I will note that the current MLB HR/CON rate in 2013 is 4.0%, the same as it was during the 1999 and 2001 seasons. Yes, it’s 116 games out of 2,430, and this could end up being nothing more than a blip on the radar, so don’t go overboard with any conclusions just yet.

However, April is supposed to be the month where the ball flies the least. The first week of April is the coldest weak of the month, on average. Because we haven’t even taken two full turns through the rotation yet, the innings totals are skewed towards each team’s best pitchers. And yet, despite all those variables that would theoretically push home run totals down, the ball is flying out of Major League stadiums at about the same rate it did during the absolute peak of the home run boom.

It could very well be nothing. 2,000 innings isn’t enough to draw any real conclusions. Maybe it’s been unseasonably warm the first week. With samples this small, a few gusts of wind and some random variation could be tricking us into seeing something that isn’t there. With that caveat, though, it is still something to keep an eye on. MLB saw an uptick in power last year, and it’s seen a very small sample uptick in power to start 2013. The rising strikeout rates are keeping the scores down enough to where it has gone unnoticed, but dingers might be making an underreported comeback in Major League Baseball right now.

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Dave is the Managing Editor of FanGraphs.

35 Responses to “The Early Trend of 2013: Dingers!”

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  1. Evan Gattis says:

    You’re welcome.

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  2. CabreraDeath says:

    *Home Run Boom, rather than Home Room Boom in the second to last paragraph, Dave.

    Also, excellent article. I didn’t catch your piece last summer regarding HR/Con. Informative stuff.


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  3. cass says:

    I thought it was pretty likely that this increase in home runs is almost certainly linked to the warm weather. To check this out, shouldn’t we take the temperature at all the games, compare it to the usual temperature at games in April, and then use the rate at which temperature affects HR’s to see how much of the increase is due to temperature?

    Do we not have good datasets for those things? They should all be out there somewhere.

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  4. Jay Owen says:

    Could this have anything to do with the fact that fences have been moved in at Citi Field (a loooot of homers hit there so far this year), and also at Safeco? And the fact that only one game has been played at Petco, and two at the Marlin’s park?

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    • joser says:

      Mariners opened on the road, so only two games have been played at Safeco (though, granted, one was last night’s slugfest… and at least three of the Astros’ home runs would’ve been warning track catches or maybe doubles with the old dimensions). The fences were moved in at Citi Field in the ’11-’12 offseason, not this past winter; perhaps you’re thinking of PetCo — but again, the Padres opened on the road and as of this morning have only played one game in their new park.

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    • S Arora says:

      Fences have been moved in at Petco too. There were 3-4 Hrs in the first game.

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  5. Blofkin says:

    This rise in HR rate is all well and good, but personally I’m more fascinated by that aggresive increase in K%. When’s the last time the league K rate was over 20% for a full season?! I mean that’s really high.

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  6. cass says:

    Another question about the K’s that I’ve never seen discussed: Who will become the first pitcher to strikeout 21 batters in a game? Obviously no one knows, but it would seem like something that would not be unexpected.

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    • jorgath_dc says:

      My prediction is that it’ll be someone who we know can get Ks but who isn’t known for LOTS of them.

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  7. Carl Karcher says:

    Conspiracy of Silence? No mention made of Joey Votto, who has not homered since June 24, 2012. That’s a span of 49 games and counting. Last year when Pujols had his April drought, it seemed to be all I read about. Double standard?

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    • Jacob says:

      Votto has a 134 wRC+ this week, and a 146 wRC+ in the second half of last year. Pujols wasn’t just not hitting dingers last April, he was slashing an ugly .217/.265/.304

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    • Menthol says:
      FanGraphs Supporting Member

      Joey had several homers during spring training, so this fantasy owner hopes that means the power will show up …

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    • joser says:

      Oh no, you’ve discovered Big Sports Media’s pro-Canadian conspiracy! Now the plans to have hockey take over from NASCAR have been set back a generation!

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    • eye-roll says:

      Votto isn’t one of the biggest names in baseball, he didn’t just sign an enormous contract, and he didn’t just debut that new contract in the largest media-celebrity market in the country. Pujols is a huge name and a Latin player moving to one of the largest Latino demographics in the US; Votto is a quiet Canadian playing in a small non-Canadian city. He didn’t elicit much commentary even when he was leading his league in HRs and MVP votes, and he plays in a flyover city that for all its baseball history most Americans know mostly for chili and a Loni Anderson sitcom. When was the last time anything of national note happened in Cincinnati? (Mapplethorpe maybe?) The situations aren’t remotely comparable, so the coverage isn’t either.

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      • Joey Votto says:

        Last time I checked I had a $200+ million contract and an MVP award.

        Point taken on where I play though.

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      • CircleChange11 says:

        Pujols had a horrible April in his walk year (2011) as well.

        I recall that getting as much, if not more press than the 2012 slow start.

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  8. Dandy Salderson says:

    The Axford Effect.

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  9. Hank G. says:

    …first week of April is the coldest weak of the month.

    I’m sure you meant week.

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  10. Aaron says:

    Serious question: what do these numbers look like with the Rogers Centre (and maybe one or two others) removed from the equation?

    The first six days of the season, that stadium was a bandbox like I’ve never seen. Balls that typically would have fallen harmlessly into a glove were instead carrying over the wall – and the ones that would have left, left with authority. Five of the six longest HRs this season! 23 dingers in six games!

    So, yeah. Might this just be a result of outlier stadiums?

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  11. S Arora says:

    Interesting read, Mr. Cameron. Small sample size, but not insignificant.
    I hope the dingers keep comin!
    Yu or Shark might the first pitcher to K 21.

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  12. PackBob says:

    If April = coldest month and there is a correlation with dingers, it shouldn’t be too hard to compare how cold this year has been compared to other years. Batters getting their timing down may be another factor and this year had a longer spring training.

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  13. Greg Rybarczyk says:

    The first week is almost always very dome-heavy schedule-wise, which may make it less typical of April than otehr weeks this month. I’m interested to see how the full month of April turns out…

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  14. Schuxu says:

    Its all about the moved in fences.

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    • joser says:

      Except it’s not. Of all the games played when this was written, only three had been played in stadiums with different outfields from last year. Try again.

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  15. Jay Hernandez says:

    Maybe Selig tightened up the ball a little bit.

    Would not surprise me

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  16. Baltar says:

    What has caught my attention the most in this early season is the number of games won by huge margins, 10 runs or more and even 15 or more. I could see this as either a cause (the bottom of both bullpens being scraped) or effect of the high HR numbers.

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