Home Runs Have Made Their Return to MLB

The drastic decline in run scoring the last few years has been a major story, especially as it related to the rise in drug testing and the end of the so-called “steroid era” in Major League Baseball. There’s no denying the fact that offense has tumbled in the sport, with the league average wOBA falling from a high of .341 back in 1999 to the .316 of today. As baseball has worked to eliminate performance enhancing drugs, scoring runs has become more difficult.

But, perhaps an underreported aspect of this story is that home runs are making their way back into Major League Baseball this year.

2010 was the first year that league average HR/9 had fallen under 1.00 since 1993, and then it declined again to 0.94 last year. These were the kinds of power outages that lent credence to the idea that drug testing had wiped out a large amount of artificial power that had been hanging around the sport for the last 20 years.

That trend continued at the start of 2012, as league average HR/9 was just 0.95 in April. However, as the weather has gotten warmer, the ball has started flying again. Here are the league average HR/9s by month in 2012:

April: 0.95
May: 1.02
June: 1.06
July: 1.07

And, not that you should care about the results from just a couple of days, but August has started out with a home run barrage – the league HR/9 is 1.23 on the first two days of this month. Here are those same HR/9s for 2011:

April: 0.91
May: 0.87
June: 0.88
July: 0.91
August: 1.08
September: 1.00

The first four months of 2011 certainly played like the dead ball era. Then, last August, home runs took a big jump, and they’ve stayed at an elevated level every month since besides April.

We’re basically now at one full calendar year with home run rates at the same level as they were about 10 years ago. They’re definitely not back to the peak levels of 2000 (league HR/9 was 1.18), but this quantity of home runs lines up pretty well with a bunch of years from the “steroid era”.

And in terms of measuring the actual change in power, we need to adjust for the real significant change in baseball over the last 20 years – the continuing and increasing rate of strikeouts. K% is at an all-time high again this year, up a full point over last year’s record high. Now at 19.6%, the average strikeout rate in Major League Baseball is having a significant depressing effect on run scoring, and is the primary reason that league offense is still down despite the return of some home runs.

So, instead of just looking at home runs per game, we should look at home runs per contacted ball, by removing strikeouts, walks, and hit batters from the equation. So, let’s do just that. Here is home run per contact for each season of the last 20 years.

Season HR/CON
1993: 3.1%
1994: 3.6%
1995: 3.5%
1996: 3.8%
1997: 3.6%
1998: 3.7%
1999: 4.0%
2000: 4.1%
2001: 4.0%
2002: 3.7%
2003: 3.7%
2004: 3.9%
2005: 3.6%
2006: 3.9%
2007: 3.6%
2008: 3.6%
2009: 3.7%
2010: 3.4%
2011: 3.4%
2012: 3.8%

We’re definitely not back at 1999-2001 levels, when home runs per contacted ball were over 4% for three consecutive years, but 2012 actually rates as the seventh highest HR/CON season in the last 20 years, and is actually higher than the rate was in 2005 — the year before comprehensive drug testing went into effect.

And, before you think that players have simply made adjustments to their swings to compensate for the lack of drugs, borrowing from their doubles and triples to get those home runs backs, the rate of doubles and triples per contacted ball has been essentially unchanged for the last 15 years. It’s at 7.1% this year, and has been between 6.9% and 7.3% every year since 1997.

When batters put the bat on the ball today, they’re just about as likely to get an extra base hit now as they were during most of the years when Barry Bonds was bathing in cream. In reality, the decline in offense now is almost exclusively about the dramatic rise in strikeouts. That historic lack of contact has masked the fact that power has made a pretty strong return to today’s baseball game, and has perpetuated the idea that steroid testing has led to dramatically different results in offensive performance.

Perhaps instead of looking at testing for PEDs, we should really be investigating the effects that the installation of PITCHF/x cameras in every park has had on pitchers and umpires. If we’re just looking for a direct correlation between two things, the rise of more accurate pitch tracking in 2007 and the drastic increase in K% over the last five years looks like an interesting place to start.

Of course, few things are ever as simple as “this happened, so that occurred”, and it’s unlikely that we can attribute all of the increase in strikeouts to the new cameras in the ballpark. After all, strikeouts had been on the rise — albeit at a slower pace — well before PITCHF/x, so this is more of an acceleration of a trend than an entirely new one. However, if we’re going to just talk about how one change may have had a strong cause-and-effect relationship on offense in the sport, we’re probably better off starting there than we are starting with the institution of drug testing in 2006.

Baseball is different now than it was 15 years ago, but it’s more about strikeouts than home runs. In reality, we have more evidence that either the pitchers or umpires have changed than we do that the hitters have undergone some significant physical transformation.