One of the great things about FanGraphs is the ever increasing number of stats and features available on the site. One of the downsides of that is that if you miss the initial announcement, things can get awfully confusing awfully quickly. In my efforts to update and expand the FanGraphs Library, I noticed a number of stats that slipped through the cracks and failed to get their own entries after debuting on the site. Today, we are correcting another one of those absences.

One of our most prominently displayed statistics is Defense, or Def if you’re checking out the leaderboards or player pages. We rolled Off and Def out about a year ago as simple combinations of stats we already offered on the site, but if you weren’t hanging out on FanGraphs in mid-September 2013, you might not have known what they meant. Def is simply fielding runs above average (Ultimate Zone Rating at FanGraphs) and the positional adjustment added together and tells you about a player’s total defensive value relative to league average. It is a cumulative stat, so it is based on the quality and quantity of your performance. To learn more about run value stats, check out last week’s entry in the Library.

As always, feel free to contact me on Twitter @NeilWeinberg44, in the comments, or during my weekly chat at 3pm eastern on Wednesdays with any and all FanGraphs and stat related questions.