GLOSSARY

The Glossary provides definitions, explanations, and links to sources for more information on words and phrases that are unique to baseball, statistics, and general analytics. If there is a word or phrase you do not see that you think should be added, please contact allcapsports@gmail.com.

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Arbitration - A process used in the MLB for players who are not eligible to free agents and could not reach a contract agreement by a set deadline with their team to negotiate their contracts. The players side provides an amount and the club side provides an amount to an unbiased arbiter who hears testimony as to why the player/club should be favored before ultimately deciding which amount is awarded.

At Bat (AB) - Plate appearances that do not include walks.

Average Annual Value (AAV) - the average annual salary for a player when considering their entire contract. (e.g., if a player has a 10-year, $100 million contract, their AAV is $10 million. In many sports / contracts, a player will not receive the same amount each year, especially when salary cap and luxury tax is concerned, so it is important to consider not only the salary for the coming year, but the average annual salary of the entire contract.)

Average Fastball Velocity (vFA) - Average velocity of a pitcher’s fastball.

Balk (BK) - An illegal pickoff move made by a pitcher which automatically sends a baserunner to the next base.

Batters Faced (BF) - Number of batters faced over a period of time by a pitcher.

Batting Average (BA) - How many hits a player gets per an at bat.

Batting Average on Balls in Play (BAbip) - How many hits a player gets per an at bat where they put a ball in play. This measures how well a player hits for contact as it does not include homeruns or strikeouts (it does include sacrifice hits).

Bunt - When a batter squares the bat to the plate in order to hit a soft grounder. If a player tries to lay down a bunt with 2 strikes, it is the only time they can be called out for hitting it foul.

Caught Stealing (CS) - When a player gets caught trying to steal a base.

Collective Bargaining Agreement (CBA) - Agreement between the MLB League office and the MLB Players Association as to rules that govern the league, including years of service before eligibility, minimum team salary, Competitive Balance Tax (CBT) and much more. The CBA was last renegotiated in 2022.

Competitive Balance Tax (CBT) - A threshold of team payroll (that is negotiated in the Collective Bargaining Agreement (CBA)) above which a team must pay additional taxes depending on how many consecutive years the team has surpassed the threshold (first year = 20%, second year = 30%, third year = 50%). The CBT for 2023 is $233 million and the thresholds are set until the 2026 season. See more information at MLB.com.

Complete Game (CG) - When a player pitches all 9 innings.

Closing Pitcher (CP) - Pitcher who normally ends the game, typically coming in in the 9th inning when the team is ahead.

Cy Young Award - Given to the best pitcher in the National League and American League each year (one awarded in each league, two total).

Double (2B) - When a player gets to second base on a hit without a fielding error.

Earned Runs Average (ERA) - Average number of runs allowed per 9 innings for a pitcher (this does not includes runs resulting from errors).

Earned Runs Average Plus (ERA+) - this is essentially the ERA statistic normalized across the league, also taking into effect external factors like opponents faced and ballpark. If league average ERA is 3.5, and a pitcher’s ERA is 3.0, the calculation for ERA+ would look as follows - 100*(3.5/3)*(external factors).

ERA Title - Award given to the pitcher with the lowest ERA in each league (given they meet the minimum innings pitched requirements).

Expected Fielding Independent Pitching (xFIP) - FIP is a statistic estimates pitcher run prevention independent of how the team performs in the field. xFIP is the same, except it replaces a pitcher’s home run total with an estimate of how many home runs they should have allowed given the number of fly balls they surrendered while assuming a league average home run to fly ball percentage (between 9 and 10% depending on the year). Refer to the Fangraphs.com Sabermetrics Library for more details.

Expected Earned Runs Average (xERA) - According to Fangraphs, “xERA uses exit velocity, launch angle, and sprint speed on “topped” or “weakly hit” balls to model what a player’s ERA would look like based on the underlying characteristics of the balls in play.” Refer to Fangraphs’ explanation for further detail.

Fangraphs Wins Above Replacement (fWAR) - An attempt to evaluate a player’s contribution to their team in one statistic, using many other statistics in the calculation. There are a few different ways to estimate efficiency on offense, defense, pitching, and other areas, and therefore there are a few different accepted methods of WAR which usually yield similar results: FanGraphs (fWAR), Baseball-Reference (rWAR or bWAR), and Baseball-Prospectus WARP (same idea as WAR, just a different name). Check out this explanation from Fangraphs to learn more about how this statistic is calculated.

Fielding Independent Pitching (FIP) - FIP is a statistic estimates pitcher run prevention independent of how the team performs in the field.

Error (E) - When a player has the opportunity to put out an opposing batter via fielding the ball, but mishandles the play allowing that runner to be safe. It is a subjective statistic where a player is given an error if it is determined they "should have" made the play.

Games (G) - Number of games a player started or entered the game.

Gold Glove - Award given to a player for being the best at their position in their league (there is an American League and National League winner each season).

Grounded Into Double Play (GIDP or GDP) - Number of times a player hits a ground ball when there is a force-out at any or all of the bases in addition to first, and 2 outs are recorded by the defense as a result.

Grounded Into Double Play Percentage (GDP%) - Number of times a player grounds into a double play per a plate appearance with a runner at least on 1st base and less than 2 outs (double play opportunities).

Hit (H) - When a player gets on base by putting the ball in play, and without a fielding error.

Hit By Pitch (HBP) - When a batter gets hit by the ball and advances to first.

Hits per 9 Innings (H9) - Number of hits per 9 innings allowed by a pitcher.

Homerun (HR) Ratio - Ratio of homeruns allowed to batters faced. If a pitcher gives up 10 homeruns in 1000 faced batters, their HR ratio would be .01. Batters faced is different than at bats - a walk, intentional walk, or hit by pitch does not count towards at bats, which is why we use batters faced to calculate this ratio.

Homeruns per 9 Innings (HR9) - Number of homeruns per 9 innings allowed by a pitcher.

Innings Pitched (IP) - Number of innings pitched by a pitcher in a certain timeframe.

Intentional Walk (IBB) - When a batter is intentionally walked by a pitcher, sending them to first base.

Most Valuable Player (MVP) - Given to the best player in the National League and American League each year (one awarded in each league, two total). Pitchers and position players are pooled together for this award.

Non-CBA Minor League Players - Players who have accrued no service time (years) in the MLB and are not on 40-man rosters. They are subject to different minimum pay requirements than CBA Minor League players who have service time and/or are on 40-man rosters. Refer to BetMGM.com for further explanation.

Offensive Wins Above Replacement (oWAR) - a metric used to analyze WAR attributed strictly to the offensive contributions of a player (it ignores defense).

On-Base Percentage (OBP) - How often a player gets on base (walk or hit) per plate appearance.

On-Base Plus Slugging (OPS) - Sum of on-base percentage and slugging percentage.

On-Base Plus Slugging Plus (OPS+) - Normalized OPS across the league, taking into account external factors, such as ballparks. Average OPS would be an OPS+ of 100, 50% better than that would be 150, and so on.

Pickoff Attempt - When a pitcher throws to a base between pitches in an attempt to get an out or keep a runner close to the base.

Quality Start Percentage (QS%) - A quality start is when a pitcher starts a game and pitches more than 6 innings. The percentage is this number divided by the number of total starts a pitcher has.

Relief Pitchers / Bullpen - Pitcher who comes in to relieve (hence the name) the starter. You are allowed a certain number of pitchers, and teams manage the number of starters in their rotation and the number of relief pitchers (which includes the closer). The relief pitchers and closer wait in a physical space called the bullpen, where they wait to be called upon to enter the game.

Rookie of the Year (ROTY) - Given to the best rookie in the National League and American League each year (one awarded in each league, two total). Pitchers and position players are pooled together for this award.

Runs Batted In (RBIs) - Number of runs a player drives in.

Runs Scored/Allowed (R) - How many times a player crosses home plate (scores). This includes runs scored off errors which does not count towards a pitcher's ERA.

Sacrifice Bunt (SH) - When a batter bunts to move a runner over on the base path, sacrificing their own out.

Sacrifice Fly (SF) - When a batter hits a fly ball to the outfield with a runner on 3rd, allowing that runner to advance home on a tag up, thus, sacrificing their own out for a team run. This counts as an RBI as well.

Saves / Holds - A hold is when a pitcher comes in and holds a lead when the team is ahead by 3 runs or less. A save is the same, except the pitcher records the final out.

Single (1B) - When a player gets to first base on a hit without a fielding error.

Strikeouts per 9 Innings (K/9) - Number of strikeouts divided by number of innings pitched times 9. For example, if a pitcher strikes out 10 pitchers in 10 innings, their K/9 would be 10/10*9, or 9.00.

Slugging Percentage (SLG) - Total number of bases a player records per at bat.

Split On-Base Plus Slugging + (sOPS+) - Same as OPS+ but is specific to the split being looked at (e.g., if you are looking at only September splits, sOPS+ will be the player's OPS for September which is relative to the league OPS for September.

Stolen Base (SB) - When a player gets from one base to the next during the pitching sequence (not while the ball is in play).

Strikeout (SO, K) - When a player gets out via 3 strikes while batting.

Strikeouts per 9 Innings (K/9, SO9) - Number of strikeouts divided by number of innings pitched times 9. For example, if a pitcher strikes out 10 pitchers in 10 innings, their K/9 would be 10/10*9, or 9.00.

Strikeout Percentage (SO%) - Percentage of all plate appearances ending in a strikeout.

Strikeout/Walk Ratio (SO/BB) - Ratio of strikeouts to walks allowed by a pitcher.

Tagging Up - When a runner on the base path moves from one base to the next on a fly out by waiting until the ball is caught before moving off the bag and then running to the next base without being thrown out.

Total Bases (TB) - Total number of bases a player has reached over a specified time period.

Triple (3B) - When a player gets to third base on a hit without a fielding error.

Unrestricted Free Agent (UFA) - Player who is available to be signed to a contract by any team for any amount.

Walk (BB) - When a player gets to first base on four balls.

Walk (BB) Ratio - Ratio of walks given to batters faced. If a pitcher gives up 100 walks in 1000 faced batters, their BB ratio would be .10. Batters faced is different than at bats - a walk, intentional walk, or hit by pitch does not count towards at bats, which is why we use batters faced to calculate this ratio.

Walks, Hits per Innings Pitched (WHIP) - WHIP essentially tells you how often a pitcher allows a baserunner per inning. There are some nuances, for example, most calculations do not include a hit by pitch as a walk, so these are not counted (although for purposes of my calculations of WHIP I did add in hit by pitch as I feel this to be more accurate, even though it doesn’t change the number much, if at all). If a pitcher lets up 250 hits, 100 walks, in 350 innings pitched, their WHIP is 1.0.

Walks per 9 Innings - Number of walks per 9 innings allowed by a pitcher.

Winning Percentage (W-L%) - The percentage of games a pitcher wins, taken by dividing number of wins by total number of games in which there is a decision made for the pitcher (if a pitcher is tied when he is removed, or the team who is winning changes after they are removed, this would result in a “no decision.” The game still is played, but no decisions do not count towards the winning percentage of a pitcher.

Win Probability Added (WPA) - Per fangraphs.com - "Win Probability Added (WPA) captures the change in Win Expectancy from one plate appearance to the next and credits or debits the player based on how much their action increased their team’s odds of winning." It is a context-driven statistic - "You get credit based on how much your action contributes to the odds of winning, meaning a home run in a 1-1 game in the 9th is dramatically more valuable (for a batter) than one in a 10-1 game in the 9th."

Wins Above Replacement (WAR) - “A single number that presents the number of wins the player added to the team above what a replacement player . . . would add.” (Society for American Baseball Research) There is not one way to calculate WAR - it is comprised of hundreds of steps and calculations to come up with the rating, through research performed by organizations such as Baseball-Reference, Fangraphs, and others.

Wins Above Average (WAA) - “A player's worth in terms of his contribution as compared to the average major league player.” (Baseball-Reference) This is derived from Total Player Rating and is used as a way to measure individual and team performance compared to major league average, while also including external factors such as era and ballparks played. The major difference between WAA and WAR is that WAR compares performance to a theoretical replacement player, typically a top-tier minor league player who would fill the position. WAR significantly favors players who play a lot because of this.

Wild Pitch (WP) - When a pitch is thrown out of the reach of the catcher.

World Baseball Classic (WBC) - Essentially like the FIFA World Cup for baseball - countries all over the world put together teams and compete against each other every 4 years.

Years of Service - In the MLB, years of service determines when you will be eligible for arbitration (3 years) and free agency (6 years). A year of service can be accrued by being on a 26-man roster or injured list (IL) of a team for 172 days, which can accumulate over multiple seasons. There are 186 days in an MLB season and the max any player can accrue in one season is 172. In the renegotiation of the Collective Bargaining Agreement (CBA) between the MLB and the MLB Players Association in 2022, a rule was added allowing players to receive a full year of eligibility even if they are short of the 172 days accrued if they place top 3 in Rookie of the Year voting.