I’m not normally one to criticize Chris Carpenter.
I spent a solid month arguing with whoever would listen about why he should win the Cy Young, and even wrote a manifesto about why he was a the best choice.
This past season was by far the best of his career (despite the fact that he actually did win the Cy Young in 2005). He compiled career-bests in ERA (2.24), WHIP (1.007), batting average allowed (.226), and OPS allowed (.581).
Unfortunately, with all due respect to Mr. Carpenter, there is no way he will put up similarly dominant numbers in 2010.
The first sign that Carpenter is in for a decline involves no sabermetric theories or heavy brain wrinkling; his age and injury history suggest that his dominance is unsustainable.
Carpenter will be 35 next season, and he’s always struggled to stay healthy. A torn labrum cost him all of 2003, and he combined for just four starts in 2006-7. This year, he missed more than a month because a strained ribcage, which probably cost him the Cy Young.
To be fair, age isn’t always a factor, and injuries are often the result of luck. Unfortunately, Carpenter has a bigger problem: His approach to pitching is fundamentally flawed.
What separates a good pitcher like Carpenter (6.8 career K/9 ratio) from a great one like Tim Lincecum (10.2) is his ability to strike out opposing hitters (or lack thereof). For whatever reason, Carpenter is a contact pitcher—he lets batters hit the ball and hopes they don’t score.
Isn’t there more to it than that? Not really, no. Anyone who has done any research into the subject will tell you that, with the exception of walks, strikeouts, and home runs, the outcome of an at-bat is out of the pitcher’s control.
If a batted ball lands anywhere within the stadium’s walls, there is a roughly 30 percent chance that it will fall for a hit. It doesn’t matter whether the pitcher’s name is Felix Hernandez or Livan Hernandez.
Carpenter was dominant in 2009 because an inexplicably small number of opposing batters reached base when they put the ball in play.
Batting Average on Balls in Play (BABIP), also known as a pitcher’s hit rate, is the measurement of this concept. Using a simple formula:
Hits – Home Runs
At-Bats – Strikeouts – Home Runs
Statisticians can easily determine which pitchers are getting lucky.
Opposing hitters earned a .274 BABIP off of Carpenter in 2009. And before you try to rationalize that with some theory about his abilities to induce poor contact, note that his career mark is .301—exactly what is to be expected.
Using Defense-Independent Pitching Statistics, a measurement that uses the factors within the pitcher’s control to estimate what his ERA would be with neutral luck, Carpenter comes out at 2.93—still very good, but .69 runs is a big difference.
This luck works both ways, as Cole Hamels would happily tell you. While expectations for his 2009 numbers were exaggerated after being named World Series MVP the year before, he could have been one of the best pitchers in the league if not for his .321 hit rate (compared to .288 for his career). DIPS transforms his ERA from an unimpressive 4.32 to an ace-worthy 3.68.
In addition to being lucky about balls landing where fielders could catch them, Carpenter was quite fortunate with the types of balls that were hit as well. Throughout his career, opposing batters have earned a 1.789 OPS against Carpenter when they hit line drives off of him.
It’s quite lucky, then, that just 20.6 percent of balls were hit for line drives, compared to 22.2 percent for his career. That might not seem like much, but it translates to about one fewer hit every two games, which can add up.
That’s not to say Carpenter won’t be good in 2010—in the last seven years, his highest ERA in a full season was 3.46. But anyone looking for him and Wainwright to repeat as baseball’s best top-of-the-rotation tandem will be disappointed.