Baseball Statistics Glossary

Jun 12, 2016; Pittsburgh, PA, USA; A major league baseball rest in the grass prior to the game between the Pittsburgh Pirates and the St. Louis Cardinals at PNC Park. Mandatory Credit: Charles LeClaire-USA TODAY Sports
Jun 12, 2016; Pittsburgh, PA, USA; A major league baseball rest in the grass prior to the game between the Pittsburgh Pirates and the St. Louis Cardinals at PNC Park. Mandatory Credit: Charles LeClaire-USA TODAY Sports /
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Basic Terms and Information

  • Earned Run Average (ERA) – The “earned runs” (runs that were scored without an error allowing them to happen) a pitcher allows per 9 innings pitched.
  • Hold (H) – Middle relief statistic for a pitcher who comes into the game in a save situation and turns the game over to another reliever without the game having been tied during his time on the mound.
  • Save (S or Sv) – Statistic for when a reliever comes in to finish out the game and preserve a win. In the modern bullpen, this is typically done by a closer pitching the 9th inning. The game must be within 3 runs for a save to be awarded, however there can be exceptions awarded if a pitcher finishes the game by pitching 3 or more innings in relief and does not receive the win in the game.
  • Strikeout (SO or K) – When the pitcher achieves 3 strikes on a batter to record an out. Often times utilized as a rate stat, either by strikeouts per 9 innings pitched (K/9) or percentage of batters faced struck out (K%). League average K/9 for starters in 2015 was 7.4 K/9 and average K% in 2015 was 19.5%.
  • Walk (BB) – When the pitcher throws 4 balls to the hitter to allow the hitter to be awarded first base. Rate stats for walks for starting pitchers in 2015 averaged at 2.72 BB/9 and 7.1 BB%.
  • Walks plus Hits per Inning Pitched (WHIP) – Spelled out in the name, adding walks and hits and dividing them by innings pitched for a pitcher.
  • Win (W) – Awarded to the pitcher who was on the mound last for the winning team when they scored the deciding run of the game. Starters must complete 5 innings to be awarded a win.

More Advanced Stuff

  • Command – The ability for a pitcher to put the ball where his catcher wants the ball, or where he wants the ball to go.
  • Control – The ability for a pitcher to put the pitch near or in the strike zone consistently. It can be very important to note difference between control and command with a pitcher when reviewing walk rates for predictability.
  • Earned Run Average Plus (ERA+) – A weighted statistic for ERA comparing a pitcher against the average pitcher in the league in the same environments. A score of 100 is right on league average, over 100 is better than league average, and under is worse than average.
  • Fielding Independent Pitching (FIP) – A statistic that attempts to normalize the “typical” behavior for all types of hits and measure a pitcher’s performance against those metrics to give a number similar to ERA that shows how many runs he should have allowed if all fielding (and luck) in the league were equal.
  • Quality Start (QS) – Statistic that measures a start by the starter’s ability to complete six innings while allowing 3 or less earned runs. Due to the volatility of the win statistic (one could get a win while giving up 10 runs if his team scored 11 runs behind him), many fantasy leagues have begun to utilize quality starts instead of wins as a statistic.

A Few Sabermetric Terms To Know

  • Expected Fielding Independent Pitching (xFIP) – Taking FIP to another level, xFIP attempts to normalize home run rate for pitchers as well as the fielding behind him by using league average home run rates on fly ball rates rather than home runs for a pitcher’s home run numbers in the calculation.
  • Game Score (GS) – A statistic originated by the innovative Bill James, game score measures the production of the starter. Computed by assigning scores to innings pitched, runs allowed, walks and hits allowed, and strikeouts. Average is 50, and maximum possible score with no baserunners is 114 if a pitcher went all 9 innings with no hits or walks allowed, striking out all 27 hitters. The highest game score in the history of the game is Kerry Wood‘s 1998 20-strikeout game against the Astros.
  • Pitch F/X – While teams have had this information for some time, only in the last couple years have fans been able to review full data on velocity, pitch type, and movement of each pitch in the system that the league calls Pitch F/X. Data on every pitch and trends on each pitch can allow the average fan to see changes that can possibly predict performance going forward.
  • Wins Above Replacement (WAR) – While this was mentioned in the hitting area, it is a different beast for pitchers. Calculating those wins above replacement utilizes different measurements for pitchers – one system will use FIP, another will use xFIP, yet another will use another proprietary pitching statistic to plug into their value metric. In general, the best pitchers are not going to grade out as well as the best hitters in Fangraphs’ version, but in Baseball-Reference and Baseball Prospectus they tend to end up fairly even.

Next: Fielding Terms