What does Roger Clemens’s on-field performance have to say in the case of McNamee v. the Rocket? The trainer alleges he injected Clemens with performance-enhancing drugs (PEDs) in 1998, 2000, 2001. Looking for signs of suspicious success, we compared the Rocket’s career to six hurlers with similar power-pitching styles. Below, season-by-season “ERA+” totals—ERA compared to the league average and adjusted for the effect that different ballparks can have on offenses. An average ERA+ is 100; a pitcher 20 percent better than average will have an ERA+ of 120, and so on.
Even among the greats, Clemens stands out. He appeared to be declining in his thirties, but put up a monster season at age 34, posting a 221 ERA+. It’s not uncommon, though, for power pitchers to take big steps well into their thirties—the real divergence came later. After two decent seasons at ages 39 and 40, Clemens won a Cy Young Award in 2004 and posted an outrageous 1.87 ERA in 2005, for a 226 ERA+ that’s the thirteenth-best of all time. The huge spike at such an age was unprecedented in major-league history.
Last week, Clemens’s management agency released a report presuming to explain how his performance could have occurred naturally. While it is correct to note the strong records of aging-power-pitcher contemporaries like those below, the fact is no one pitched as well, as late, as Clemens. Nor is he cleared by research from the blog Sabernomics, which found little evidence of jumps in performance after the injections McNamee alleges. The problem with this analysis is there’s little information on the effects of PEDs on pitchers. They can increase muscle mass and thus fastball speed; some also believe they speed injury recoveries and allow one to work out more often, increasing durability. Clemens could have taken PEDs preemptively—preventing falloffs rather than triggering spikes—or taken doses too small to have an effect. And, of course, he could’ve taken PEDs on other occasions.
Our own statistical comparison is itself flawed—we can’t be sure the pitchers we compared Clemens to were themselves “clean,” though none have ever been accused of using. So it’s a piece of completely circumstantial evidence which might be the most damning. There’s one other player—a hitter, rather than a pitcher—who recently enjoyed success far beyond what any other player his age had ever achieved. The evidence suggesting this player used steroids, though, is quite strong and comes from a wide variety of sources. That player’s name is Barry Bonds.
Jonah Keri has written about baseball for ESPN.com, Baseball Prospectus, Salon, and other publications.