Steroids' statistical effect under review
After Mitchell Report, numbers trends can now be examined
It's become a shorthand for the remarkable offensive explosion of the past 15 years -- the "steroid era" in baseball. Run scoring spiked up in the early 1990s and never really came back down, and the glib explanation is that all the sluggers bulked up on "juice" and started drilling the ball out of the park.
With the release Thursday of former Sen. George Mitchell's report on illegal performance-enhancing drugs in baseball, the picture of the past 15 years became a bit clearer. We know a little more about who was doing what, and a good bit more about how the culture came to be.
There can be little doubt that many offensive achievements in recent years were accomplished by players using PEDs. But the more information that comes out, through Senator Mitchell's report and through suspensions, the more it is clear that hitters weren't the only ones using the substances. Thirty-one pitchers were named in Mitchell's report.
Offense is up, but it's not just the chemicals.
"I've always thought there have been a number of factors at play throughout the '90s and now into the early 2000s," said Bruce Markusen, baseball historian and author of eight books on the game.
"Certainly steroids have been a part of it. There has been a trend towards smaller ballparks with the new stadiums. There have been a lot of advances in hitting instruction, hitting theory, video-based hitting instruction. I think that's been a change that doesn't always get a lot of publicity, but that's been a factor as well."
And the exact effect of using the substances is yet to be determined. Most believe that the extra strength helps, but just how much is uncertain. Whether it's 10 feet on a fly ball or 30, whether it's one homer or 10 in a season, these are questions that remain unanswered.
In light of the report, though, the answers may start to become clearer. The additional data will allow the stat-savvy to begin parsing information and trying to identify trends.
"So far, we haven't done very much [to adjust numbers for steroid use]," said Nate Silver, proprietor of Baseball Prospectus' PECOTA statistical projection system.
"Until 36 hours ago, we hadn't had this list of players who did steroids. We had some Minor Leaguers, but not at the Major League level so much. I have looked separately at some of the Minor League numbers, starting back in '05, and we've found there wasn't that much of a difference as far as production went. Maybe guys gained 15-20 points of ERA for pitchers or 25 points of OPS for hitters. But it wasn't night and day. Looking at the commission names may be kind of the same thing."
With time and research, then, the context will become clearer. The accomplishments within the context, meanwhile, are already under a bright light. The two greatest practitioners of the one-on-one pitcher-hitter battle in recent decades have both been named in connection with the issue.
Barry Bonds, the most dominant offensive force baseball has seen since at least Ted Williams, saw a stout case laid out against him in the book Game of Shadows. Roger Clemens, one of perhaps two candidates for the title of greatest pitcher of the past generation, was named in Mitchell's report as a purchaser and user of illegal performance-enhancing drugs. Clemens has vehemently denied the accusations, with his attorney calling them slanderous.
So while the broader question of an offensive era is heavily layered, the issue of these two superstars' performances is more direct and immediate. If the accusations are true, to what extent is the legitimacy of Bonds' and Clemens' performances compromised or even destroyed?
Markusen believes that Bonds begins with a strike against him, so to speak, because of the context. In his view, all home run marks are compromised in the current era, due to the combination of steroids, smaller ballparks and the variety of other hitter-friendly factors in play.
But he argues that Bonds' record should nonetheless stand.
"Let me first say that I absolutely don't think we should be putting any asterisks next to any records," he said. "I don't think you can rewrite history. Every era has different conditions, different factors."
But with that said...
"In terms of the milestones, certainly with all the factors in the game that have helped the offenses over the last 15-20 years, I don't think there's any question that some of the milestones we've come to respect have been cheapened."
There's a case to be made, then, that although Clemens may have benefited from PEDs -- and it's extremely important to note that he has vehemently denied the accusations -- he has also had to fight an uphill battle in some ways. The game is stacked against the pitcher.
But Clemens, like Bonds, stands out for one reason -- his staggering accomplishments beyond the ages where most players start petering out. And while correlation does not imply causation, one reason that players take steroids and other illegal drugs is to improve recovery. That's the sort of thing that becomes even more vital at later ages.
So if Bonds and Clemens were in fact aided by chemicals, one way it would manifest itself is in their late-career performances.
According to baseball-reference.com, Clemens' most similar pitcher after his age-40 season was Tom Seaver. In Seaver's age-41 year, he went 7-13 with the second-worst ERA of his career. It was his last big league year. Second on the list was Steve Carlton, who never had a full and effective season after his age-39 campaign.
If in fact Clemens' numbers are tainted, it's the career numbers, more than the single-season markers, that will be most in question.
In Bonds' case, it's both. According to the accusations leveled against him in Game of Shadows, he was very much a steroid user by his record-setting 73-homer rampage in 2001. That record is surely clouded, at the least.
But the era itself remains a slipperier question. Individuals absolutely abused steroids and other performance-enhancing drugs, and likely gained some statistical benefit from doing so. But the league-wide effects remain under review.
Matthew Leach is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.