Here’s what we get when we assign weights to pitchers strikeout totals based on the frequency their victims strike out in general. For example, Mark Reynolds strikes out about once every 2.9 plate appearances, and the league average is 5.4, so a strikeout of Mark Reynolds is only worth about 0.54 in “Strike equivalent difficulty” (Ked – I’d subscript the “ed” in that label, but then I’d have to find out how). Juan Pierre, on the other hand, strikes out very rarely – once per 15.6 plate appearances, so striking him out is worth 2.9 Ked.
Felix Hernandez has a commanding lead in strikeouts by difficulty – his 232 actual strikeouts have the equivalent difficulty of striking out 261 batters with average strikeout rates. 131 (or 56.4%) of his Ks have been recorded against batters who strike out less often than the league average. He’s the only pitcher to throw 10 strikeouts against batters whose PA per K rate is at least double the league average, and the closest competitor has only 7. Among pitchers with 200 strikeouts this year, he’s the only pitcher who has thrown more than half of his strikeouts against batters who are better than average at not striking out.
Here are the top 30 in 2010 for Strikeout equivalent difficulty (Ked):
|Pitcher||Actual Ks||Ked||Ked – K||Ks vs above average batters||Ks vs batters above 1.5 * average||Ks vs batters above 2 * average|
The three columns on the right indicate strikeouts against batters who are above the major league average in plate appearances per strikeout (about 5.4); strikeouts against batters who are better than 1.5 times league average (about 8.1); and strikeouts against batters who are better than double the league average strikeout rate (about 10.8).
Hernandez’s 10 most difficult strikeouts have been against Alberto Callaspo, David Eckstein (twice), AJ Pierzinski, Joe Mauer (three times), Kurt Suzuki and Jason Kendal (twice). He’s also struck out Miguel Tejada once, Orlando Cabrera once, and Vlad Guerrero 5 times, and all those guys strike out less often than once per 10 plate appearances.