Cameron: Introducing Fielding Dependent Pitching

The idea for FDP was to quantify the remaining aspects of run prevention that are not measured by walks, strikeouts, and home runs. With a FIP-based WAR, we have a metric that tells us how many wins a pitcher added through success in those three key areas. What we did not have was a metric that gave us the wins added through either hit prevention or runner stranding. With FDP, we wanted to be able to break down the remaining aspects into those two categories, so that we could identify exactly where a team’s run prevention — with a specific pitcher on the mound — was coming from.

To do that, we simply worked backwards. First, we calculated the total WAR that a pitcher would receive credit for if he was only evaluated by his runs allowed, and we assumed that he had 100 percent responsibility for every variable that influenced run scoring. That stat is now on the site, and is called “RA9-Wins”. If you do not want to consider any impact of fielding on run prevention, and solely want to evaluate a pitcher by what actually happened when he was pitching (accounting for park and league adjustments, at least), then this is the metric for you.