A brief explainer of some of the stats used on our site.
Pitching Stats:
ERA: Earned run average represents the number of earned runs a pitcher allows per nine innings — with earned runs being any runs that scored without the aid of an error or a passed ball. The formula for finding ERA is: 9 x earned runs / innings pitched. If a pitcher exits a game with runners on base, any earned runs scored by those runners will count against him. (MLB)
FIP: Fielding Independent Pitching (FIP) measures what a player’s ERA would look like over a given period of time if the pitcher were to have experienced league average results on balls in play and league average timing. (Fangraphs)
K/9 / BB/9 / HR/9: Strikeouts Per 9 Innings (K/9), Walks Per 9 Innings (BB/9), and Homeruns Per 9 Innings (HR/9) are rate statistics that measure how many strikeouts and walks a pitcher averages over nine innings. (FanGraphs)
BABIP: Batting Average on Balls In Play (BABIP) measures how often a ball in play goes for a hit. (FanGraphs)
Hard-hit Rate: Statcast defines a ‘hard-hit ball’ as one hit with an exit velocity of 95 mph or higher, and a pitcher’s “hard-hit rate” is simply showing the percentage of batted balls that were allowed by the pitcher that were hit at 95 mph or more. (MLB)
Barrel: The Barrel classification is assigned to batted-ball events whose comparable hit types (in terms of exit velocity and launch angle) have led to a minimum .500 batting average and 1.500 slugging percentage since Statcast was implemented Major League wide in 2015. We present this as a percent of barrels allowed per batter faced. (MLB)
Hitting Stats:
OPS: OPS adds on-base percentage and slugging percentage to get one number that unites the two. It’s meant to combine how well a hitter can reach base, with how well he can hit for average and for power. (MLB)
wRC+: Similar to OPS+, Weighted Runs Created Plus (wRC+) measures how a player’s wRC compares with league average after controlling for park effects. League average for position players is 100, and every point above 100 is a percentage point above league average. (FanGraphs)
ISO: Isolated Power (ISO) is a measure of a hitter’s raw power and tells you how often a player hits for extra bases. (FanGraphs)
K% and BB%: Strikeout rate (K%) and walk rate (BB%) measure how often a hitter walks or strikes out on a per plate appearance basis.. (FanGraphs)
BABIP: Batting Average on Balls In Play (BABIP) measures how often a ball in play goes for a hit. (FanGraphs)
Hard-hit Rate: Statcast defines a ‘hard-hit ball’ as one hit with an exit velocity of 95 mph or higher, and a player’s “hard-hit rate” is simply showing the percentage of batted balls that were hit at 95 mph or more. (MLB)
Barrel: The Barrel classification is assigned to batted-ball events whose comparable hit types (in terms of exit velocity and launch angle) have led to a minimum .500 batting average and 1.500 slugging percentage since Statcast was implemented Major League wide in 2015. We present this as a percent of barrels hit per at-bat. (MLB)