Position Players
Average EV (average exit velocity): average velocity at which ball exits bat when put into play
Average LA (average launch angle): average angle at which ball exits bat when put into play
AVG (average): hits divided by at-bats
BABIP (batting average on balls in play): non-home run hits divided by non-home run balls in play
BB/K (walk-to-strikeout ratio): walks divided by strikeouts
BB% (walk percent): walks divided by plate appearances, multiplied by 100
BsR (base running): amount of runs above/below average a baserunner is, encompassing (failed) stolen bases, (failing at) advancing bases, and (not) avoiding grounding into double plays
Contact% (contact percent): swings on which batter makes contact divided by swings, multiplied by 100
Def (defense): amount of runs above/below average a fielder is, encompassing fielding performance (in form of ultimate zone rating) and a positional adjustment
DRC+ (deserved runs created plus): percent above/below average a batter’s expected performance is
DRS (defensive runs saved): amount of runs above/below average a fielder is, at a certain position
F-Strike% (first-pitch strike percent): first-pitch strikes divided by plate appearances, multiplied by 100
HBP% (hit-by-pitch percent): hit-by-pitches divided by plate appearances, multiplied by 100
HR/FB% (home run divided by fly ball percent): home runs divided by fly balls, multiplied by 100
ISO (isolated power): slugging percentage minus average
K% (strikeout percent): strikeouts divided by plate appearances, multiplied by 100
Max EV: max velocity at which ball exits bat when put into play
O-Contact%: swings on which batter makes contact on pitch out of zone divided by out-of-zone swings
O-Swing%: out-of-zone swings divided by out-of-zone pitches, multiplied by 100
OAA (outs above average): amounts of outs above/below average a fielder is, at a certain position; for infielders, it takes into account distance fielder has to travel in order to reach ball, amount of time fielder has, and distance fielder is from base runner is heading towards once ball is reached; for outfielders, it takes into account distance fielder has to cover in order to make catch and amount of time fielder has
OBP (on-base percentage): [times batter reaches base by hit, walk, or hit-by-pitch] divided by plate appearances
Off (offense): amount of runs above/below average a player is offensively — sum of base running runs above/below average and batting runs above/below average
OPS (on-base percentage plus slugging percentage): [times batter reaches base by hit, walk, or hit-by-pitch divided by plate appearances] plus [total bases divided by at-bats]
OPS+ (on-base percentage plus slugging percentage plus): on-base percentage plus slugging percentage, on a scale where 100 is league average, adjusted for ballpark and league
pBB% (predictive walk percent): incorporates chase region swing percent plus regressed, walk percent plus regressed, strike percent plus regressed, and contact percent plus regressed
pwOBA (predictive weighted on-base average): uses regressed strikeout percent, pBB%, regressed HBP%, and predictive weighted on-base average on contact
pwOBAcon (predictive weighted on-base average on contact): incorporates (standard deviation)launch angle plus regressed, under percent plus regressed, barrel percent plus regressed, sprint speed plus regressed, 10th percentile exit velocity plus regressed, 50th percentile exit velocity plus regressed, and 90th percentile exit velocity plus regressed
SB% (stolen base percent): stolen bases divided by stolen base attempts, multiplied by 100
SLG (slugging percentage): total bases divided by at-bats
Sprint speed: average speed of around two-thirds of a player’s fastest one-second window runs, including “Runs of two bases or more on non-homers, excluding being a runner on second base when an extra base hit happens [and] Home to first on ‘topped’ or ‘weakly hit’ balls” (Baseball Savant)
Swing%: swings divided by pitches, multiplied by 100
SwStr% (swinging strike percent): swings and misses divided by pitches, multiplied by 100
UZR (ultimate zone rating): amount of runs above/below average a fielder is, at a certain position
WAR (wins above replacement): amount of wins above/below replacement a player is; there are three main versions: fWAR (FanGraphs), bWAR (Baseball-Reference), and WARP (Baseball Prospectus)
wOBA (weighted on-base average): “measure[s] a hitter’s overall offensive value, based on the relative values of each distinct offensive event” (Slowinski)
wOBAcon (weighted on-base average on contact): wOBA except it only considers results on balls in play
wRC+ (weighted runs created plus): percent above/below average a batter’s performance is, adjusted for ballpark and league
xBA (estimated batting average): “expected” hits divided by at-bats; it is based off of exit velocity, launch angle, and, sometimes, sprint speed
xSLG (estimated slugging percentage): “expected” total bases divided by at-bats
xwOBA (expected weighted on-base average): weighted on-base average except it uses expected weighted on-base average on contact instead of wOBAcon
xwOBAcon (expected weighted on-base average on contact): wOBAcon except it uses expected results on balls in play
Z-Contact%: swings on which batter makes contact on pitch in zone divided by in-zone swings
Z-Swing%: in-zone swings divided by in-zone pitches, multiplied by 100
Zone%: pitches in zone divided by pitches, multiplied by 100
Pitchers
BB/9 (walks per nine innings): walks divided by [innings pitched divided by nine]
CSW% (called strikes plus whiffs percent): [called strikes plus whiffs] divided by pitches, multiplied by 100
DRA (deserved run average): estimated number of runs a pitcher deserved to allow per nine innings
ERA (earned run average): earned runs allowed per nine innings
FIP (fielding independent pitching): estimates earned run average based on strikeouts, walks, hit-by-pitches, and home runs allowed — all of which are fielding independent
FIP- (fielding independent pitching minus): fielding independent pitching, on a scale where 100 is league average, adjusted for ballpark and league
HR/9 (home runs per nine innings): home runs divided by [innings pitched divided by nine]
K/9 (strikeouts per nine innings): strikeouts divided by [innings pitched divided by nine]
K-BB% (strikeout minus walk percent): [strikeouts minus walks] divided by batters faced, multiplied by 100
pBB% (predictive walk percent): incorporates ahead in count swing percent plus regressed, wOBAcon denominator percent plus regressed, and strike percent plus regressed
pCRA (predictive classified run average): an earned run average estimator that incorporates walks, strikeouts, barrels, topped, and under batted ball events
pK% (predictive strikeout percent): incorporates shadow region swing percent plus regressed, waste region swing percent plus regressed, heart region whiff percent plus regressed, average fastball velocity plus regressed, and strikeout percent plus regressed
pwOBA (predictive weighted on-base average): uses pK%, pBB%, regressed HBP%, and pwOBAcon
pwOBAcon (predictive weighted on-base average on contact): incorporates topped percent plus regressed and hard hit percent plus regressed
SIERA (skill-interactive earned run average): an earned run average estimator that incorporates walks, strikeouts, relationships between fly balls and ground balls, etc.
WHIP (walks and hits per inning pitched): [walks plus hits] divided by innings pitched
xERA (estimated earned run average): same as estimated weighted on-base average except it is on ERA scale
xFIP (estimated fielding independent pitching): same as fielding independent pitching except it estimates home runs allowed using league average home run divided by fly ball percent
xFIP– (estimated fielding independent pitching minus): xFIP, on a scale where 100 is league average, adjusted for ballpark and league
Sources on which you can find one or more of these stats
- Baseball Savant
- FanGraphs
- This site
- Baseball Prospectus
- Baseball-Reference
- Pitcher List
- Six Man Rotation (dead)