Pitching and Defense, Part I

The thing about pitching is that, except for Rob Deer's three true outcomes (Home Run, Walk, Strikeout) what happens is entirely out of a pitcher's control. This leaves a pitcher's effectiveness, fantasy and otherwise, open to the effects of defense. This opens up fantasy pitching to several lines of analysis, all of which I hope to get into at some point.

In the first part of this series, I want to start with the idea that pitchers who have a sub-par defense behind them have their fantasy stats affected either directly or indirectly. Technically speaking, errors don't contribute much to fantasy performance. It deprives pitchers of an out (if your league counts, for example, innings pitched), but doesn't count directly against WHIP, ERA, Ks, Wins, or Saves. It does, however, put more pressure on the pitcher. It forces the pitcher to throw more pitchers, potentially shortening the outing. It may move a runner into scoring position, or force the pitcher to change from a wind-up to a stretch delivery, or any number of other adjustments that can affect a pitcher later in the inning or game. This can in turn affect ERA (more pitchers = more potential mistakes), WHIP (ditto), Wins (unearned runs = more runs the pitcher's team has to score), etc.

For this analysis, I decided only to focus on the top-50 fantasy pitchers from the last five years as determined by standard fantasy points scoring. Bad defense was defined as any team in the bottom 20% of fielding percentage for the year. Fielding percentage isn't a great fielding metric, but since it is essentially the number of errors over the number of balls in play (subtracted from one) it accounts directly for errors as a percentage of plate appearances that don't result in one of the three true outcomes.

This left us with 250 pitchers, and 39 of them qualified as having a bad defense behind them, or 15.6%. This is less than the expected 20%, but not significantly so. Using a simple student's t-test, I then calculated if these 39 pitchers had significantly different stats from the remaining 211 top-50 starters.

Surprisingly (or perhaps not), no statistics were significantly affected. There was no significant difference in wins, losses, ERA, WHIP, Home Runs Allowed, Fantasy Points, Strikeouts, Walks, Pitchers Thrown, Innings Pitched, OPS against, or Strikeout Rate. Absolutely none of the 20-ish variables I looked at differed based on team fielding percentage.

Now, this was only for the top-50 fantasy starters every year. These are, by and large, elite pitchers. This makes it a non-representative sample- higher strikeout rates, more pitching skill (as opposed to just throwing), etc. The numbers may be different outside the top 50. But there's no reason to shy away from a highly-rated pitcher because of a bad defense.