MLB Glossary

Hitting Stats:

  • TG (Team Games): Total number of games played by the team.
  • HR (Home Runs): Total number of home runs hit by the team.
  • BB% (Walk Percentage): Percentage of plate appearances that result in walks (bases on balls).
  • K% (Strikeout Percentage): Percentage of plate appearances that result in strikeouts.
  • BB/K (Walk-to-Strikeout Ratio): Ratio of walks to strikeouts.
  • ISO (Isolated Power): Measure of a hitter’s raw power, calculated as slugging percentage minus batting average.
  • BABIP (Batting Average on Balls In Play): Percentage of balls hit into play that result in hits.
  • AVG (Batting Average): Average number of hits per at-bat.
  • OBP (On-Base Percentage): Percentage of plate appearances that result in the batter reaching base.
  • SLG (Slugging Percentage): Measure of a hitter’s power, calculated as total bases divided by at-bats.
  • wOBA (Weighted On-Base Average): Comprehensive measure of offensive production, weighted for each type of hit and walk.
  • wRC+ (Weighted Runs Created Plus): Adjusted measure of runs created by a hitter, relative to league average and park factors.
  • Barrel% (Barrel Percentage): Percentage of batted ball events with optimal combinations of exit velocity and launch angle.
  • HardHit% (Hard Hit Percentage): Percentage of batted ball events with an exit velocity of 95 mph or higher.
  • SB (Stolen Bases): Total number of stolen bases by the team.
  • CS (Caught Stealing): Total number of times a runner is caught stealing by the opposing team.


Pitching Stats:

  • G (Games): Total number of games pitched.
  • GS (Games Started): Total number of games started by the pitcher.
  • IP (Innings Pitched): Total number of innings pitched by the pitcher.
  • IP/G (Innings Pitched per Game): Average number of innings pitched per game started.
  • K/9 (Strikeouts per Nine Innings): Average number of strikeouts per nine innings pitched.
  • BB/9 (Walks per Nine Innings): Average number of walks issued per nine innings pitched.
  • HR/9 (Home Runs per Nine Innings): Average number of home runs allowed per nine innings pitched.
  • K/BB% (Strikeout-to-Walk Ratio Percentage): Percentage of strikeouts relative to walks.
  • BABIP (Batting Average on Balls In Play): Percentage of balls in play that result in hits.
  • LOB% (Left On Base Percentage): Percentage of baserunners left stranded by the pitcher.
  • GB% (Ground Ball Percentage): Percentage of balls in play that are ground balls.
  • FB% (Fly Ball Percentage): Percentage of balls in play that are fly balls.
  • HR/FB (Home Run to Fly Ball Ratio): Ratio of home runs to fly balls.
  • ERA (Earned Run Average): Average number of earned runs allowed per nine innings pitched.
  • xERA (Expected Earned Run Average): Expected earned run average based on underlying pitching statistics.
  • FIP (Fielding Independent Pitching): Pitching statistic that focuses solely on the events a pitcher has the most control over: strikeouts, walks, hit by pitches, and home runs.
  • xFIP (Expected Fielding Independent Pitching): Expected fielding independent pitching based on league-average home run rates.
  • WHIP (Walks plus Hits per Inning Pitched): Average number of walks and hits allowed per inning pitched.
  • SIERA (Skill-Interactive Earned Run Average): Pitching metric that estimates a pitcher’s run prevention independent of team defense.
  • WAR (Wins Above Replacement): Measure of a player’s value compared to a replacement-level player.