Based on the success of my "MLB's 10 Most Effective Curveballs" and "MLB's 10 Most Effective Sliders" articles, I decided to look at the 10 most effective changeups in 2009.
I'm measuring changeup effectiveness by Pitch Type Linear Weights, which says how many runs a pitcher prevents above average every time he throws 100 pitches.
So, if I say a changeup's effectiveness is one run above average, that means that every 100 changeups that pitcher throws, he allows one run less than average.
I set two ground rules. First of all, pitchers have to have thrown at least 30 innings this year. Second, they have to use the changeup at least 10 percent of the time.
For each pitcher, I'll list the average changeup velocity, average changeup movement relative to an average major league fastball (if you want to know why I'm comparing it to a fastball, just ask), changeup usage (how often the pitcher throws the changeup), and changeup effectiveness (as measured by Pitch Type Linear Weights).
Also, just to clarify, this is me taking the leaderboard on changeup effectiveness, listing the top 10 pitchers, and analyzing their changeup's success. This is NOT a subjective list.
So don't tell me I'm "leaving somebody off." It's just the leaders in the stat and my analysis for why they're leading.
Let's take a look.