So, if “steroids” are not the primary cause of the offensive boom of the nineties (which continues in a reduced form today) what is? Well, first, I don’t believe in single causes, and there are a number of things that have created the current situation.
Second, I’ve written a piece that got away from me, tracing the rise in offense; I moved that behind the fold. Anyway, the reasons I think that offense has risen…
Technique: Batting technique today is rather different from what it was a couple of decades ago. Players stand almost on top of the plate — the batter’s box essentially does not exist — and umpires don’t enforce the rules about getting out of the way of the pitch. There is no inside of the plate anymore. Meanwhile, they’ve learned to hit the ball, hard, to the opposite field. Stats, Inc. did a study a few years ago, based on some comments by Greg Maddux that the biggest difference in the game from when he was a young pitcher was that when he came up you rarely saw home runs to straightaway opposite field, while now they happened all the time. The study showed that this was so, and that a huge amount of additional home runs were being generated this way.
“Steroid” caveat… It may be that PHD allow hitters to hit these opposite-field homers that would otherwise be outs. I don’t know, but I think that would be, at most, a contributing factor.
Also, hitters are increasingly taking an all-or-nothing approach at the plate. Walks and strikeouts are also both up, trends seen throughout baseball history. Which brings me to…
Trends: As I mention in the out-of-hand history segment below, home run totals have tended to rise throughout baseball history, since 1919 anyway. There were two major but short-term dips — World War II and its balata ball, and the 1960s strike zone redefinition — but one major long-term dip. Home runs per game plunged in about 1974 for reasons I’m not sure of. They recovered in the AL, probably due to DH effects, but not in the NL, where they rose again but only slowly. 1993-97 NL baseball was essentially a return to historical norms, but homers kept going up for a few years after that. Every year since 1998 has averaged at least one homer per team per game. Only once in NL history before that, in 1955, had teams averaged a home run a game.
Equipment: Notably the long, thin-handled bats. They break a lot, but if you don’t care — and these guys get their bats free — they’re a lot more effective at knocking the snot out of the ball than the old table legs were.
Parks: Notably, Coors Field, but the new park in Arlington and the addition of Phoenix have brought lots of runs into the majors, especially homers. The replacement of the Astrodome with Your Name Here Field marked the end of a long series of moves to increase run scoring in Houston. Dodger Stadium and Kauffman Stadium have been remodeled to be more hitter-friendly.
Turf: A subset of the above. The widespread demise of artificial turf has done a lot to make teams focus on power-hitting. The chop hits fast players used to get on turf, gone. It also decreases the incentive to hit a line drive, increasing that to hit it in the air. At the same time, it’s taken the pressure off of outfield defense, allowing 1950s-style sluggers to move back into the outfield corners. In the 1980s, there were lots of little fast guys playing left field, particularly on teams managed or influenced by Whitey Herzog. Those guys are gone now or have to make it in center. Vince Coleman would never have a job today.
Little Fast Guys: (The following is a paraphrase of Bill James.) Pitchers used to wind up, I mean really wind up. These days, only Paul Byrd has a traditional windup, plus a few Latin pitchers with unusual deliveries, and there’s Dontrelle Willis. That’s it. It seems likely that shortened deliveries, intended to control the running game, mean that pitchers don’t throw as hard, or aren’t as deceptive. (Alternatively, the “steroids era” has only allowed them to throw as hard as they used to, while batters have improved.)
Cal Ripken: Wait a minute, he’s retired! But Ripken is one of the most influential players in the game still, because he (at the direction of Earl Weaver) broke the stereotype that shortstops have to be little fast guys, that a 6-4, 225-pound guy couldn’t play shortstop. He had help, notably Ryne Sandberg, a 6-2, 185-pound second baseman. Once, players like the late AL shortstop trinity would have been moved to the outfield, just as Aaron, Mays, and Mantle were. Even Miguel Tejada, who’s listed a 5-10, might well have been — he’s just about Aaron’s height. Jeff Kent would have had to make it as a third baseman if he were born fifteen years earlier. Simply put, a lot of bad-hitting infielders were replaced by good-hitting outfielders because some of the great hitters were now being allowed to play infield.
Weight training: Just remember, weight training is new in baseball, as in “practically unknown before 1980”. So you’d expect bigger and more muscular players even if they didn’t take anything more than aspirin.
Summary: I’m pretty sure all these things have had an effect. I’m not sure that “steroids” has. Probably. If it has, I’m pretty sure it’s not as big as the changes in batting technique and the bats themselves. There may be interaction, though — stronger players can take better advantage of the technique, for example. Certainly it’s hard to see some of these big, muscular guys waddling around left field in a turf park in 1985. (Though Greg Lusinski did.)
One last point… Before 1998, two men had hit 60 home runs in a season. Now five have. Maris still holds the AL record. Home run numbers today are higher than in the past because there are more home run hitters, not because the home run hitters generally are more impressive. In a lot of ways, it’s the ridiculous homer numbers of just three men that’s driving this.
National League runs scored numbers have historically been pretty consistent, wobbling around about four runs per team per game from 1931 (when they deadened the baseball) to 1992 (the run explosion really began about 1993). 1968, the year of the pitcher, was basically the only year of the liveball era where RPTPG dipped significantly below four, at 3.43; the next lowest year was 3.81. The American League has been a little more volatile; it was the pitcher’s league before the DH was introduced, but at other times, such at the late forties/early fifties had been more hitter-friendly. League home run totals, however, have generally risen over time; in recent years, home runs per game have been more than one, something that only happened once in the years before 1986.
There was a big fluke year in 1987, one nobody’s ever explained. Wade Boggs hit 24 homers, which to you younger folks would be like, I don’t know, Ichiro hitting 40. Mark McGwire, as a rookie, hit 49, as did Andre Dawson over in the NL. It’s a pedestrian total now, but marked the highest in the game since George Foster’s 52 in 1977, the most in the AL (which was still a tougher place to hit, just had more hitters) since 1969. Then things went back to normal for a little while, when all hell broke loose in 1993.
Now, 1993 was an expansion year, and people always blame expansion for everything that changes. In that case, there was probably a little merit in it for the NL, at least, because the Rockies entered the league. Mile High Stadium wasn’t quite the hitter’s haven that Coors Field has proved, but it did bring a whole lot of runs into the league. That doesn’t explain why RPTPG went from 4.32 to 4.71 in the AL, or why they went even higher to 5.23 the next year. The NL went from 3.88 in 1992 to 4.49, but the former was on the low side so the jump looks more dramatic than it really was. But then it went up again, to 4.63, and stayed in that range for the next few years. AL numbers have continued to be volatile in recent years. The NL jumped to 5.00 in 1999-2000, then settled back into the 4.60 range of 1993-98. In 2005, it fell to 4.45, the lowest of the era (tying 2002). Maybe that’s the “steroid effect”, .15 to .2 RPTPG. Not insignificant. But it might just be one of those things. .2 RPTPG isn’t outside normal variance. Home runs per game dipped to 1.01, also the same as in 2002, but higher than pre-1999 rates.