Last week, I examined how much hitters benefit from facing a poor defense. This week I thought I’d keep with a similar theme and examine how much hitters benefit from facing a poor starting pitcher.
What pitchers affect
Well, just about everything. This may be obvious to some, but in today’s world, nearly every fantasy writer out there is writing about things like BABIP and HR/FB (even if they don’t always know what they’re talking about), so it’s possible that some of us are of the opinion that facing a poor pitcher will only benefit a hitter’s strikeouts, walks, and batted ball profile (i.e. things that a pitcher “controls” under DIPS Theory).
The control a pitcher has over various stats is a discussion for another day, but the short explanation is that pitchers actually have control over everything, just to varying degrees. A pitcher has a lot of control over his K rate but very little over his BABIP, for example. He does have some control over the hits he gives up, though, and if he’s good in terms of DIPS numbers (strikeouts, walks, etc.), he’s more likely to prevent hits. How much of this translates to a hitter’s performance against such a pitcher is one question I was hoping to answer with today’s study.
To study the effects of the starting pitcher on hitting, I’m going to look at all regular season games played since 2002 and compare how hitters fared against pitchers of varying quality. To measure pitcher quality, I’m using end-of-season xFIP.
I’m only including hitters that had at least three plate appearances in a game to help eliminate things like injuries and pinch hitters and focus on what we daily leaguers care about – the player who’s starting today. Additionally, I’m only including pitchers who threw at least 90% of their seasonal innings as a starter since a pitcher will post a much better xFIP as a reliever.
I broke the pitchers down into half-point xFIP buckets. Here are the results for each category for each bucket:
What he see here is that facing a when facing an elite pitcher, a hitter’s production goes down drastically across the board. The only place where it doesn’t seem to make any difference is stolen bases, which makes sense. Pitchers do have some control over the steals they allow, but xFIP doesn’t capture this. Perhaps I’ll look at this in another article. Triples also seem random-ish, but there is a general pattern where it’s better to face a bad pitcher in terms of triples; there’s just a little more variation with it.
With everything else, however, there is a clear pattern. Against elite pitchers, a hitter’s home run rate will be sliced by a quarter! Against a terrible pitcher, though, it’ll rise by a fifth! Those figures are enormous. We also see huge effects for walks, RBIs, and runs.
Looking at our early question in regard to hits, it definitely seems like a hitter can outperform (or underperform) in the hits categories based on the pitcher he’s facing. The effects aren’t as large as home runs or walks, but they are definitely there.
The above table might be a little intimidating, so here is a clear breakdown of how this all affects your FanDuel team. To the right is a chart that lists the overall points per day a hitter would produce against each type of pitcher, followed by the approximate FanDuel dollars that would translate to (using a basic regression equation I created).
What we see here is that the difference between a hitter facing an elite pitcher and a terrible pitcher is over $400 FanDuel dollars per hitter per day! That’s absolutely enormous!
Like last week, this study was conducted knowing who the good and bad pitchers would be for the year ahead of time. At the start of a season, we can’t be certain which pitchers are good and which are bad, though we do have a pretty good idea, especially for pitchers who have been around a while. It’s pretty safe to say that Roy Halladay is good and Livan Hernandez is bad.
Derek Carty’s work can also be found at The Hardball Times Fantasy and DerekCarty.com. He has previously had his work published by NBC’s Rotoworld, Sports Illustrated, FOX Sports, and USA Today. He is the youngest champion in the history of LABR, the longest-running experts league in existence, and is a graduate of the MLB Scouting Bureau’s Scout Development Program (aka Scout School). He welcomes questions via e-mail, Facebook, or Twitter.