Down the Rabbit Hole: Maybe MLB Knows Why Balls Are Hopping Off Bats

Scott WeldonCorrespondent IAugust 20, 2009

When Mark McGwire first hit 70 home runs in a Major League Baseball season, it became apparent to everyone who was paying attention that something was wrong. 


During the era before McGwire's 1998 assault on the record books, from just after Roger Maris hit his 61 home runs in a season until 1993, only three players in major league baseball hit 50 home runs or more in a season.


Willie Mays hit 52 to lead the league in 1965. George Foster hit 52 with the Big Red Machine in 1977. Cecil Fielder hit 51 in 1990.


It was hard, almost impossible, to hit 50 home runs in the major leagues.


Hank Aaron, in his entire storied home run hitting career, never hit 50 in a season.


Mike Schmidt was one of the best home run hitters in history. He led the majors in home runs for six seasons, including three in a row. McGwire led the league five times (tying with Andre Dawson in 1987).  


Schmidt’s season best totals were 36, 38, 38, 48, 31, and 40. People were being asked to believe that Mark McGwire was twice the home run hitter Mike Schmidt was. It was not credible.


In the past, teams often hit fewer than 100 home runs in a season. Teams that hit more than 200 home runs in a season were noteworthy. They got nicknames—see Harvey’s Wallbangers in Milwaukee.


The 1977 Red Sox hit 213 home runs. The Brewers in 1980 hit 203. Detroit in 1991 hit 209.


Generally speaking, around five clubs a year would hit fewer than 100 HRs. The year 1987 sticks out as the exception.


In 1986 the Tigers led the league with 198 home runs. The only team with fewer than 100 was the Cardinals with 58.


The 1988 team leader in home runs had 158. There were five teams with fewer than 100 home runs that year.


During the 1987 season five teams hit more than 200 home runs. The Cardinals were the worst team in the league again, but with 94 home runs this time.


After this anomalous year, HR hitting reverted to the norm. From 1988 to 1993, only one team hit more than 200 HRs in a season, and 23 teams during those six years had a season of fewer than 100 HRs. 


The strike years of 1994 and '95 came along, and because only partial seasons were played it wasn’t immediately apparent that home run numbers were up.


Approximately 70 percent of a season was played in '94 and 89 percent of a season in 1995. When you extrapolated what teams had done for their partial season to a full season, you’d see that in 1994 three teams would have hit more than 200 home runs, and none would have fewer than 100. In 1995, the extrapolated numbers would be four and zero.


Certainly these numbers were not alarming but interesting. For 12 years, from 1996 to 2007, 89 major league baseball teams hit more than 200 HRs in a season. No team in that time period hit fewer than 100 HRs.


Apparently in 1994 it suddenly had become impossible for a major league ball team to hit fewer than 100 home runs in a season. What happened an average of five times a year for the previous 30 years had become instantaneously impossible. It went from being commonplace to impossible like the flicking of a switch.


In 2008, four teams hit over 200 home runs, and the San Francisco Giants became the first team since 1993 to hit fewer than 100 home runs in a season with 94.


What is to be made of all these bizarre numbers?


I decided to take a look at HR hitting historically in major league baseball. I got the HR totals league-wide for Major League Baseball from 1898 to 2008, and I also collected the AB totals league-wide and decided to use the HR/AB number to suggest how likely it was to hit home runs in the big leagues every year.


This gave me a huge sample size and what I thought should be a relatively constant number from year to year.


The league-wide seasonal HR/AB number turned out to be much more variable than I had anticipated. From 1898 until 1919, the putative end of the dead-ball era, there was a wide range of HR/AB from season to season. It ranged from .00624 HR/AB to .00309 HR/AB. There was an average of .00473 HR/AB hit over that period.


There was around half a percent chance each time a player had an AB in that era of a home run being hit.


Baseball instituted a better, more tightly-wound ball in 1920 and provided more of them so teams wouldn’t be forced to play an entire game with one or two balls, as had happened in the past. They would play with baseballs until they were literally pounded to pieces, often going into the stands after home runs and foul balls to get the ball back to play with.


No doubt this is the era that gave birth to the expression knocking the cover off the ball. The new ball showed a marked improvement in home run hitting league-wide. From 1920-28 the average stood at .01120 HR/AB. This was more than double the rate of home run hitting seen in the dead-ball era. 


During the great depression and until America’s entrance into WWII, there was another marked and consistent increase in home run production. The average for this 13-year period was .0158 HR/AB. This was a jump of 41 percent league-wide that remained fairly steady through the '30s. 


World War II brought a huge dip in home run hitting back to 1920s levels, but after the war home run hitting climbed quickly and then more gradually to a zenith in 1961.


From 1947 until 1966, the rate that home runs were hit per at bat averaged .0241 HR/AB. This average represented another 50 percent jump in average home run production every year. This increase occurred gradually and topped out from 1955 to 1964. The HR/AB rate increased above .0250 in 1955 for the first time in history, and eight years out of the next 10 stayed above that historic mark.


The 1961 season saw Roger Maris break Babe Ruth’s record for most home runs by a player in a season with 61 versus 60. That year saw the highest ever HR/AB ratio in major league baseball. That year, batters hit a home run every 35.5 ABs.


The HR/AB ratio was .02814. Major leaguers were hitting home runs 2.8 percent of the time they experienced an AB. This number remained the highest for a season in major league baseball until 1987.


Maris’ breaking of Ruth’s record caused consternation, protest, asterisks, and articles.


One of the theories put forward for Maris’ ability to hit 61 home runs in a season was that the ball being hit in 1961 was livelier than the one hit by Ruth in 1927. Major League Baseball denied there was any difference in the balls both in 1961 and at the end of the dead-ball era. They were certainly mistaken the first time.


After Maris hit his 61, major league home run production declined. From 1967 until 1986 there was much greater variability in HR/AB, but the number on average was lower.


For example, during that period of time the HR/AB climbed above .0250 only four times in 20 years. This is in stark contrast to the nine times it occurred in the previous 12 years.


The average during this period was .02218, less than the .0241 seen during Maris’ era (1947-1966). This came despite several attempts at the time to increase offense, including dropping the pitcher's mound from 15 inches to 10 in 1969, a decrease in the strike zone, and the institution of the DH rule in the American League in 1973.


Still, 1987 was, as I noted above, an anomalous high home run year and is still one of the highest HR/AB years in history at .03094. Right after 1987, baseball returned to six years much like the 20 before 1987, averaging .0224 HR/AB.


Then came the strike years and beyond. Aside from 1987, every year from 1994-2008 has had higher HR/AB per season than any earlier year in history.


The average HR/AB through this period is .03111. This represents approximately a 37 percent sustained increase in HR hitting league-wide above the average rate from 1969-2003, which was .02293. During those 15 years home run hitting has not sunk below .02900 HR/AB.


Major League Baseball is on pace again to hit home runs over three percent of the time a player has an at-bat. Roger Maris’ league-wide rate in 1961 of .02814 pales in comparison.   


Why has this happened? Steroids have taken the blame. Anabolic steroids have been around and in use in professional and amateur sports for more than four decades.


It’s very unlikely that the players in Major League Baseball suddenly found out about steroids in 1993 and then all started using in 1994 and received an instantaneous boost in HR production above whatever boost the pitchers were getting. Throw in the anomalous 1987 HR hitting year, and that explanation makes no sense at all.


Furthermore, players are now tested for steroids. Theoretically, that’s having some impact on how many major league players are using them, and if they’re responsible for the increase in home runs being hit, I’d expect an equal decrease now that players have theoretically stopped using.


The HR/AB numbers for 2007 and 2008 were .02954 and .02926. This is quite a bit less than the previous year's .03219 or the average of .03116.


Unfortunately, these numbers are still higher than any pre-strike numbers in baseball history (except 1987). They’re higher than 1961’s .02814 and comparable to the strike year numbers of .02998 and .02945. 


This increase in home run production is what I’d expect if they pulled the fences in by 30 or 40 feet.


The easiest way to increase offense and not get caught doing it would be to produce a baseball that bounces 37 percent further. It has the virtue of being done successfully before.


In my scenario, MLB tests a rabbit ball in 1987. At the time there were questions about steroids and a rabbit ball in MLB. Those questions went away when there were no repeated huge home run years following 1987.


In 1994, in preparation for a strike, MLB reintroduced the 1987 rabbit ball to boost offense and help win fans back after the strike. They’ve run with it ever since.


By doing so they’ve invalidated the single-season and career home run records. Everyone's power numbers remain unevaluated from the strike forward. 


Is Mark McGwire a better home run hitter than Mike Schmidt? I don't think so, but I can't tell. The numbers tell me nothing. 


The crazy home run numbers that people are putting up certainly fed the frenzy to find out if players were using steroids. I’m sure steroid use contributes to home run production, but I imagine it’s been doing so for 30 years and has gradually increased league-wide HR/AB totals as more and more players started using.


I can’t see steroid use instantaneously increasing home runs/AB by 37 percent from one year to the next. I believe that MLB is disingenuously letting the steroid-using players take the entire rap for goofy home run numbers.  


There’s been a quantum shift in the number of home runs hit league-wide. Some pervasive variable has to have been changed to account for it.


I think they’ve juiced the ball and ruined the greatest records in professional sports in the process to get fans back after the strike. It seems shortsighted to me, but attendance is high and fans seem happy.


What more could a professional sports league want?     



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