A guide to all of the complex stats that I use

SEATTLE, WA - MAY 3: Seattle Mariners general manager Jerry Dipoto (R) talks with manager Scott Servais before a game. (Photo by Stephen Brashear/Getty Images)
SEATTLE, WA - MAY 3: Seattle Mariners general manager Jerry Dipoto (R) talks with manager Scott Servais before a game. (Photo by Stephen Brashear/Getty Images) /

Below is a guide to all of the more complex baseball stats that I like to use here on Sodo Mojo or Call to the Pen

You have probably reached this page because you clicked on the link to one of the stats that I used in a post on Sodo Mojo or Call to the Pen, so look below for the stat that you were interested in figuring out what it means and I hope that I can help you become a more informed baseball fan.

Or, maybe if you are learning the game and want to impress your friends who seem to be speaking a foreign language when they get into sabermetric stats, use this page as a study guide and then drop an “xBA” in there every once in a while with them.

Qualified: A term that is not actually a statistic, but for pitchers and hitters “All qualified hitters/pitchers” means that it just includes players who have hit a specific milestone for that season to say that they have played most of the games. It keeps players with a 1.500 OPS or 0.00 ERA in only 4 games played out of the league leaderboards for stats when the season is a few months in.

WAR: The best stat for what a player is valued. The number is how many wins that player brings the team over what a replacement player could bring to the team. Baseball Reference says if you have a WAR of 8.0 you are MVP level, 5.0 All-Star level, 2.0 everyday starter, and then below 2 you are a backup. You never want to be in the negatives for WAR.

dWAR: It is the same as WAR, but while WAR measures defense and offense, dWAR (Short for defensive WAR) just measures defense. It is my favorite stat for measuring defense since it is so hard to measure defense with stats like errors and fielding percentage.

xERA: A pitchers expected ERA (xERA) is simply what you could expect the pitcher’s ERA to be based on the advanced statistics instead of what actually happened on the field, since the pitcher could have got lucky and instead of having a low ERA he could have a much higher ERA.

ERA+: Measured on a scale with 100 being the average. It measures a pitchers ERA including ballpark effect since all ballparks are different and some are better/worse for pitchers. It is also great to see where a pitcher is compared to the league average ERA.

OPS+: Same as ERA+ but with OPS.

xBA: Same as xERA but for batting average. anything with “x” in front of it is going to be “expected” and is based on advanced statistics instead of the actual result on the field.

xSLG: Same as xERA and xBA but for slugging percentage.

xwOBA: Expected weighted on-base average. wOBA is like an on-base percentage but there are different weights for hits like doubles and home runs. This one is hard to explain and MLB.com has a more complete explanation which you can read by clicking here.

FIP: “Fielding independent pitching.” It measures pitchers’ effectiveness at not letting up homers, walks, hitting pitchers, and then also getting strikeouts. Every year it is set so the league average is the same as the league average ERA, so you usually want your FIP to match, or be better than your ERA.

Exit Velocity: This has become more mainstream but it is how hard the ball is hit off the bat. For hitters, it is how hard they hit it off the bat, and for pitchers, it is how hard their pitch was hit.

Hard Hit %: the percentage of times that a hitter hits a ball, or pitcher lets up a hit ball, over 95 miles per hour.

Barrel %: A really cool stat that just means the percentage of time a hitter hits a ball, or a pitcher lets up a hit ball, with a combination of an over .500 xBA and 1.500 xSLG. It basically means the percentage of the time the player hits one on the barrel of the bat.

K %: Strikeout percentage.

Fastball Velocity: Speed of the pitchers’ fastball.

Fastball Spin: The rate that the pitchers’ fastball spins. When a fastball spins more it is harder to hit. Just imagine how hard it is to hit a 100 mph fastball coming at you but then imagine it starts spinning away from you!

These are also my favorite sites to play around with and look at stats, and each has some great things about them when it comes to learning about the game.

Baseball Reference

Baseball Reference is your one stop shop for looking up stats for any player who has ever played in the major leagues. It has your standard stats, but you can also dive deeper and they have your more advanced stats as well.

Baseball Savant

Baseball Savant is awesome for many reasons. For pitchers and hitters, you can see how they fare against the rest of the league in some more complex, but easy to understand statistics. For pitchers, you can also see what types of pitches they throw and see what the average velocity on their pitches are, as well as locations.


FanGraphs is a great site for all baseball stats regular and complex and is especially great if you are trying to look at league leaders in certain statistics.