Double Edged Plate

Watching the world series I developed the impression that Yankee pitchers were more effective at keeping the ball on the outer and inner edges of the plate than the Phillies pitchers were. I investigated with pitch f/x data. First, I defined my 2 "edges" of the plate. The pitch f/x strikezone stretches from about -0.8 ft to 0.8 ft in their coordinate system, so I defined the right edge (inside for righthanded batters) as -1.5 ft to -0.5 ft and the left edge as 0.5 ft to 1.5 ft (inside for lefthanded batters). During the entire series Yankee pitchers hit these edges with 55% of pitches to the Phillies 48%, suggesting that yes, the Yankees were more adept at keeping the ball near but not over the plate. To see if these percents are important, I then graphed opponent on base percent against percent of balls thrown to the edges for each game of the series.


As shown above, there was literally no correlation between hitting these edges and the offensive production of the opposing team in this series. This somewhat surprised me but then again I'm not taking into anything like count, type of pitch, stuff, so maybe it shouldn't have. Looking at the edge data however did reveal at least one pretty clear signal. In the series the Yankees pitchers hit the right edge 242 times and the left edge 245 times (out of 889 total), whereas the Phillies hit the right edge 272 times but left edge only 157 times (out of 886 total). The Phillies were much less balanced, as it seems they were trying to keep the ball away from the lefty power on the Yankees. The only game where the Phillies were balanced was game 1 where Cliff Lee hit the right edge 27 times and the left 31 times, which of course was an excellently pitched game.

So was balance actually important in the series? First, I defined balance as the difference between right and left edges hit divided by total edges hit (the smaller the number the better the balance). Then I plotted this against opponent on base percentage in the series. The results are below.


Now there is a correlation, albeit a weak one. The point which appears to be somewhat of an outlier in the top left is the Yankee pitchers in game 1, which was probably due to Sabathia having great balance and then a small sample size of Yankee relievers giving up a ton of baserunners. If we just look at the Phillies pitchers for the series, balance appears to be very important indeed.


In any case, this correlation doesn't prove causation, but it is interesting to see how Phillies pitchers mostly pounded one side of the plate after game 1. Theoretically this just doesn't seem like a recipe for success to me, as it allows the Yankee lefties to sit on the outside corner (Damon's 2 out single off Lidge in game 4 and Matsui's 2 run single off Pedro in game 6 both come to mind).

If anyone wants to investigate the data further, I uploaded it here (note: my if statements are in open office format, not microsoft)