Anyone with even a passing familiarity with the 2011 New York Yankees knows they have one of the best offensive attacks in the league. They are edging out the Boston Red Sox and Texas Rangers for the most runs scored in baseball this season, and it's hard to find a true weakness in the lineup to exploit. The Yankees hit at home and on the road, against lefties and righties, against fly-ball pitchers and ground-ball pitchers. With apologies to the late great Dr. Seuss, this team would score runs in a box, with a fox, in a house or with a mouse.

Looking at the pitch-by-pitch stats against the Yankees on FanGraphs, however, tells a story of a lineup with a weakness this season. The Bronx Bombers have been the best team in baseball this year at hitting fastballs, generating 81 more runs of production against fastballs than the average team. Only five teams in baseball are even 20 or more runs better than average against fastballs this season, so that 81 is a pretty impressive number. But the Red Sox and Rangers, who are also very good fastball-hitting teams this year, also have more balance. For example, the Red Sox and Rangers rank second and third in baseball against changeups. Against changeups and curveballs, the Yankees are a combined seven runs below average, a relatively weak performance for a team that is leading baseball in runs scored.


Against curves, Nick Swisher is hitting .154 and Brett Gardner is at .138. Even MVP candidate Curtis Granderson is hitting just .212 against the ol' No. 2. Derek Jeter is hitting .120 against changeups, Russell Martin .109.

Relative struggles against the curve and change are a new phenomenon for the Yanks. Last season, the Bombers were third in baseball against both pitches. A year before that, they were second in both.

For whatever reason, the Yankees have mostly fed on fastballs this season. The question this raises is whether it's a real effect or simply one determined by chance or the particular mix of pitchers the Yankees have faced.

To answer this question, I used FanGraphs' pitch-by-pitch stats to collect the pitch-type distribution for every pitcher that has faced the Yankees this season, to see if the pattern remained. In other words, to see if fastball pitchers were struggling with the Yankees more than one would expect, while pitchers who throw more curves and changeups were doing better than expected. I used the last three years of pitch distributions for pitchers, just to get a larger sample size of pitch information.

The first group I looked at was the 15 pitchers who threw the highest percentage of fastballs over the last three seasons. When I combined their numbers, this group of hurlers has a cumulative ERA of 6.04 against the Yanks in 146 innings pitched. Now, this doesn't tell us by itself that the Yankees specifically were able to take advantage of these pitchers -- we have to take the additional step of comparing it to their actual season totals. For these 15 pitchers, I took their seasonal ERAs in non-Yankees games and weighted the innings pitched in proportion to the number of innings they faced against the Yankees. The eventual weighted ERA for these pitchers in non-Yankees games comes out to an ERA of 3.96. Essentially, facing the Yankees caused the pitchers who have thrown the most fastballs to lose just over two runs a game in ERA. The rest of the American League has a 5.20 ERA against the Yankees' lineup, compared to a league average of 3.97 (difference of 1.23), so on first glance, it looks like the pattern holds.

Now the flip slide. The 15 pitchers who threw the highest percentage of curveballs have a 4.27 ERA against the Yankees in 129 innings this year compared to a weighted ERA of 3.56 in non-Yankees games. That increase of 0.71 earned runs per game against the Yankees is barely a third of the 2.08 earned-run-per-game increase that the 15 fastball pitchers suffered in 2011. For the 15 pitchers who threw the most changeups, the difference was even less, only increasing from a 3.50 non-Yankees weighted ERA to a 4.03, just over a half-run a game.

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So which teams are in a position to take advantage of this? Of the possible playoff teams, the Red Sox fare the best, with Josh Beckett and Clay Buchholz (assuming he can get back on the field) ranking among the most curveball- and change-heavy pitchers in baseball. Of pitchers who have faced the Yankees this season, they rank fourth and fifth respectively behind James Shields, Gio Gonzalez and Ricky Romero. The Rangers and Indians have a harder climb, with more pitchers who rely on fastballs and/or sinkers to get batters out. The Tigers, White Sox and Angels finish in the middle.

Perhaps the most disheartening thing for a potential playoff opponent of the Yankees is that with the talent in the lineup, there's no guarantee that the trouble hitting curves and changes will continue. As noted, the Yankees crushed both types of pitches in 2009 and 2010, so simply throwing a few more off-speed pitches might not be enough to shut down this juggernaut. However, New York's poor numbers against curves and changeups gives opposing pitching staffs a glimmer of hope.