Throw It Like a Ballplayer

providing baseball commentary and ponderings since April 2010

Punctuated Home Run Equilibrium: Part IV

Posted by dannmckeegan on May 28, 2010

This is the fourth entry in a series surveying the history of home run rate increases and decreases in Major League Baseball.  J.C. Bradbury, author of The Baseball Economist, argued both in that book and in a January entry on his website that the effect of steroids on the home run rate in baseball has been marginal compared to other potential sources, such as talent diffusion through expansion and a concerted effort to produce more tightly wound baseballs.

The introduction, published Tuesday, was simply a breakdown of some initial thoughts on the topic.  Part Two examined the rate of home runs per game as it changed in the 1920s and into the 1930s.  Part Three, a considerably longer piece, explored the post-World War II era all the way through the expansions and rule changes of the 1960s and 1970s.

Today’s article will look at the 1980s up through the last days before the 1993 expansion.  The DH rule and the lowered mound were well entrenched.  Pitching styles and managerial habits of staff handling were evolving.  Baseball players were no longer encouraged to avoid the gym, for fear of becoming “muscle-bound.”

The fifth part, focusing on the “steroid era” and drawing together the information from all of the previous pieces, will be published next Monday.  Simply, even an incomplete glance through the 1980s is too long for a darn blog.

The Wild 80s: Wave #4

The growth of the home run rate between 1981’s low point of around .63 HR/G and the 1987 high of 1.05 is the most drastic spike yet.  However, that is not a linear increase as such.  .63 was not the true beginning point, and 1.05 was not the actual end point.  By now it should be clear that both the peaks and the troughs – when large and not repeated by adjacent numbers – are themselves somewhat anomalous.  They have more to do with either the hitters or pitchers accessing a legitimate short-term upper hand.  If we look at 1979, 80, 82, 83 and 84, we’d see a trend of .75-.80 HR/G as a norm.  Likewise, we see that 1982, 83, 84, 88, 89, 90, 91 and 92 are all pretty close to one another.  So outside of a dramatic one-year trough in strike-shortened 1981 and a 3-year uptick between 1985 and 1987, the home run rate was relatively stable for almost a fifteen year stretch between 1978 and 92.

HR per G chart

J.C. Bradbury's chart of HR/G from his Sabernomics website. As stated in previous entries, I disagree with the inclusion of year-to-year line segments connecting independent data points.

There are, then, a few questions.  How related are that trough and uptick?  Is the latter something of a market correction, where offense suddenly breaks out against once-dominating pitching before again reaching equilibrium?  And why do we begin to see a best-fit line sloping downward from .9 HR/G in and around 1960 to 0.7 HR/G in and around 1990 (once we stop staring in distracted awe at a few fluke seasons)?

As we saw previously with the career years of Hartnett and Wilson, and later with the dropping production of Musial and company, individuals have an effect.  Now, any given player is much less significant to the whole in a 26 team league compared to a league of 16.  But when many players are entering the majors, establishing themselves as starters, or simply developing their game simultaneously, strange things happen.  An example of this occurs during this 1980s period, with a number of teams experiencing drastic roster turnover at a more-or-less identical point.

Take the Minnesota Twins as an example.

The 1980 roster produced only 99 home runs, or 0.61 HR/G.  In 110 games in the strike-shortened following year, they managed only 47 – a home run once every 85.64 plate appearances!  The names are largely the same on those two rosters, though the playing time is different: the catching done by Butch Wynegar and Sal Butera; Rob Wilfong, Roy Smalley and John Castino on the infield tossing to first basemen Ron Jackson and Danny Goodwin; Pete Mackanin backing up the infield; and Hosken Powell earning plenty of time in right field.

Fast forward to the following year, back from the strike.  The Twins of 1982 hit 147 home runs, good for 0.91 HR/G and a homer every 41.32 plate appearances as a team.  What happened?  Kids happened:

  • 24-year-old Catcher Tim Laudner hit 7 HR in less than 350 PA, with Butera/Wynegar contributing 1 total in 250 PA of their own.
  • 22-year-old First Baseman Kent Hrbek hit 23 HR in 591 PA.
  • 23-year-old Third Baseman Gary Gaetti hit 25 HR in 565 PA.
  • 21-year-old Right Fielder Tom Brunansky hit 20 HR in 545 PA.
  • 23-year-old Designated Hitter Randy Johnson (not that one) hit 10 HR in 271 PA.
  • And 28-year-old sophomore Left Fielder Gary Ward hit 28 HR in 616 PA.
Twins 82: Future Stars

Well, this might be a little bit of that 1981 to 1982 turnaround. Punctuated occurrence, if you will. In fits and start, new stars are born. And when it rains, it pours.

The Twins turned over all four corner positions from placeholders into power-hitters.  And over the next few years, they continued to produce talent who had some pop in their bats.  The brought up catchers Dave Engle and Mark Salas, second baseman Tim Teufel, shortstop Greg Gagne, outfielder Randy Bush, and a Hall of Famer named Kirby Puckett.  All of that happened between 1982 and 1985.  Was this isolated?  Or was there simply a massive and largely inexplicable influx of talent in the early 80s?  Well, let’s explore…

Detroit is another interesting case…

…whose story traces back to 1977, when 19-year-old Alan Trammell, 20-year-old Lou Whitaker, and 21-year-old Lance Parrish got their first tastes of the big leagues.  That year was also the rookie season of left fielder Steve Kemp, who was traded for slugger Chet Lemon after 1981, and the second season for 22-year-old first baseman Jason Thompson, who paced the 1977 team with 31 HR and 105 RBI.  Thompson was later traded in an ill-advised deal.  By 1979, they had a solid core in Parrish, Thompson, Whitaker, Trammell, and Kemp – all between 21 and 24 years of age.  Twenty-two-year-old outfielder Kirk Gibson, who wouldn’t become a regular until 1981, had a cup of coffee in 1979, as well.  By 1980, the middle infield tandem was still yet to develop their pop, but the loss of Thompson in favor of past-his-prime Richie Hebner didn’t help.

Lance Parrish

The oft-overlooked Lance Parrish, a solid catcher and great power hitter of his era.

In 1982, 23-year-old Glenn Wilson and his 12 home runs (in a CF platoon with Gibson – age 25, 8 HR) joined the emerging pop of Trammell (24 y.o., 9 HR) and Whitaker (25, 14), an elite Parrish (26, 32), and newcomers Lemon (27, 19) and Larry Herndon (28, 23) in the Detroit lineup.  A 21-year-old third baseman who shares his name with a motel chain also debuted as a bench player on this 1982 club.  Of course, Howard Johnson would match his breakout prime year (age 26) with the 1987 boom year.

By 1986, the Parrish-Whitaker-Trammell-Gibson core was well into its prime, but they were joined by 24-year-old 3B Darnell Coles, a failed Mariners prospect acquired for pitcher Rich Monteleone.  Catching prospect Matt Nokes, at 22, had a cup of coffee before his breakout age-23 season in 1987, when he hit 32 of the Tigers’ 225 HR, good for third in the AL RotY voting.

Ages and Eras

It would be pretty easy to go through other teams and find young players coming in.  Some teams had more success than others.  But in lieu of additional case studies, let’s simply look at the ages of players used by MLB teams between 1979 and 1989, as compared to HR/G rates.  Looking through that 11-season span, there are no apparent patterns, per se, in the weighted ages of the average batter and pitcher (weighted according to AB and G by  Both numbers in this time period range exclusively between 28.0 and 28.8 years.  The biggest year-to-year changes, however, happen to correlate with the years of the trough and peak.  In 1981, when HR/G were at their third-lowest level in decades, hitters were, on average, 0.4 years older than in 1980, while pitchers were 0.3 years older.  Assuming that attrition will generally pick off the older weak players, killing their playing time and eventually retiring them, a jump of this size says that the league in 1981 saw more veterans and fewer young players enter into the game on a regular basis.  Specifically, the hitters aged from 28.2 to 28.6, while pitchers went from 28.0 to 28.3.

Hitters remained between 28.6 and 28.8 years of age, on average, through 1986.  Pitchers in this period stayed between 28.3 and 28.5.  The league did proceed to age a bit.  But from 1984 through 1986, the average pitcher age was stable.  HR/G increased, but not quite as fast as the year before or year after.  And then, from 1986 to 1987, pitchers aged 0.1 years (28.3 to 28.4 years).  But the age of the average batter plummeted by 0.4 years all the way down to 28.3 from 28.7.  Again, we must ask if these occurrences are interrelated.  The average hitter is almost half a year younger than the previous year: that is approximately equal to 400 years subtracted from MLB’s total combined batter age.

This merits additional study, certainly.  The primary implication would NOT be that youth or age or shake-ups lead, by nature, to HR/G fluctuations.  Obviously, that likely would be the case, much as player fluctuations are able to do so on a specific basis.  The implication, rather, would be that over a relatively short period of time, a relatively large pool of hitters with relatively strong skill sets arrived on the scene and forced their way into lineups across baseball.

This would also explain the short period of rise: primes are short, and scouting reports are long.  It’s easy to find holes and, eventually, exploit them once the pitching talent catches up.

The late 80s into the early 90s were rather stable.  Many people think of 1988-1992 as a mini-Golden Age, and I believe that its stability without utter predictability is a large part of its appeal.  There were hitters in their primes; great pitchers and a full generation of closers fully embracing the role; a game embracing more and more Latin-American players; obvious Hall of Famers in their twilights and primes, plus kids who would later provide Hall of Fame careers.


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