Hoping to understand Alfonso Soriano's hot and cold streaks this year, I turned to the incomparable Fan Graphs to break down his present and historical success against different pitches. The results suggest that Soriano is losing the skill that made him one of the more feared hitters in the game, but that he might have found a method to compensate for this loss. Below is a chart showing the percentage of fastballs Soriano has seen each year since 2005, with 2009 broken down per month. It also shows his ranking among hitters seeing the fewest fastballs, his "runs above average" number on fastballs, (wFastball) and how high he ranks among all hitters, and his overall OPS. (As in, not specific to fastballs) The most important thing to notice here is his wFB rank.
|Date||Fastball%||FB% Rank||wFastball||wFB Rank||OPS|
You probably have noticed a couple of striking trends going on here. First, Soriano has progressively moved from being one of the most effective hitters in baseball against the fastball to being quite pedestrian. Second, pitchers have not noticed and adapted to this change: They contiue to avoid throwing fastballs to Soriano as if he were the same hitter he was in 2005. He's not.
So how do we explain Soriano's April and July, when he hit like the hitter for whom the Cubs offered that premium contract?
Finding that answer requres looking at Soriano's results swinging at sliders.