Taking Advantage of the Pitcher

It is no secret that National League pitchers get the benefit of facing the opposing team’s pitcher instead of a designated hitter. It should also come as no surprise that starting pitchers get much more of this benefit than relief pitchers as relief pitchers are far likelier to see pinch hitters (still a pretty big advantage over the standard DH) than the other pitcher. In fact, while the gap between the league average starting pitcher in the AL and NL is about a third of a run per nine innings, the gap for relief pitchers shrinks to about half of that. If you are considering a pitcher switching leagues, remember that the switch affects starters about twice as much as it does for relievers.

Which pitchers took advantage of facing other pitchers most often? I may eventually get into a far more complete answer to this, but I originally was just poking around strikeout numbers I had on hand when I decided to parse the data in this fashion. First, here are some general numbers. Looking at 2009 and only at pitchers with at least 100 batters faced, the average strikeout rate was 18% of all batters and 17.5% of all non-pitcher batters. Pitchers struck out an average of 32% of opposing pitchers that they faced.

Which pitchers boosted their strikeout rates the most against other pitchers? Over the small sample of 109 batters faced, that distinction goes to Eric Milton who had 20 strikeouts totals but just 14 against actual batters so 30% of his strikeouts came against other pitchers. Taking away those pitchers, his strikeout rate falls from a slightly above average 18.3% to a notably below average 14% giving just one example of the important of context.

Amongst slightly bigger sample sizes (300 batters faced or more) comes names like Chris Young (24% of strikeouts came against pitchers), Ross Detwiler (23%) and Craig Stammen (23%). Looking at full time starters only (greater than 600 batters faced) beings up John Lannan (21%), Zach Duke (21%), Ted Lilly (19% thanks to a whopping 58% K rate against pitchers) and the person I wanted to highlight, Joel Pineiro (19%).

Why did I focus on Pineiro when I sorted the list? Because he’s the top pitcher in this ranking who is switching leagues to the AL, where he is no longer going to get the regular benefit of facing other pitchers. Obviously people have already factored that in, but most likely in a more general sense based on the average league translation. I’m pointing out that Pineiro is a prime candidate (low strikeouts to begin with) to be hit harder than most.

Pineiro struck out just 10.6% of “real” batters last season. Any regression in his strikeout rate that fans expect should be tempered by the lack of pitchers that he will get to pitch against in 2010 which is part of the reason I agree much more with the CHONE and ZiPS projections for Pineiro (~2.75 WAR in 2010) than the Fans (3.4 WAR).