Glossary: Pitching

For hitters: Singles
For pitchers: Singles Allowed
For positions: First Baseman

For hitters: Doubles
For pitchers: Doubles Allowed
For positions: Second Baseman

For hitters: Triples
For pitchers: Triples Allowed
For positions: Third Baseman

Hitters: Batting average
Pitchers: Batting average allowed

Average number of pitches per start

Singles per plate appearance

Doubles per plate appearance

Triples per plate appearance

A pitcher's average on batted balls ending a plate appearance, excluding home runs. Based on the research of Voros McCracken and others, BABIP is mostly a function of a pitcher's defense and luck, rather than persistent skill. Thus, pitchers with abnormally high or low BABIPs are good bets to see their performances regress to the mean. The league average for modern pitcher BABIP is around .300.

Hitter BABIP is much more of a skill, based on how well they are able to hit and place the ball, along with their speed.

Equation:

BABIP = (H - HR) / (AB - K - HR + SF + SH)

Hitters: Base on balls (walks)
Pitchers: Base on balls (walks) allowed

Bases on balls allowed per 9 innings pitched.

Walks per inning pitched

Total expected run value from bequeathed runners (runners who are on base when the pitcher left his games).

Expected runs value from bequeathed runners for which the exiting pitcher is responsible

Bequeathed baserunners of the exiting pitcher prevented from scoring. The difference between expected runs and scored runs.

Bequeathed runners who scored.

Bequeathed runners for which the pitcher is responsible. More simply, the number of runners a pitcher left on base when exiting the game, excluding runners still on base put there by a preceding pitcher.

The number of runners a pitcher left on base when exiting the game who eventually scored.

Not recorded 1876-1880.

Measures how many more or fewer of the bequeathed baserunners subsequent relievers allowed to score than would be expected from league average performance in those situations. I.e., a positive figure means the following relievers kept more of the bequeathed runners from scoring than expected, negative means more of the runners scored than expected.

Blown Quality Start

Formula:

BR9 = (( H + BB + HBP ) / IP ) * 9

Occurs when a pitcher comes into the game in a save situation and surrenders the lead at any point during his appearance. The runners that score may be inherited from another pitcher, but the blown save is still charged to the pitcher who allowed them to score. Assigned for both closers and middle relievers.

Number of balls seen (batter) or thrown (pitcher)

Bequeathed runs prevented from scoring. Measures how many more or fewer of the bequeathed baserunners subsequent relievers allowed to score than would be expected from league average performance in those situations. I.e., a positive figure means the following relievers kept more of the bequeathed runners from scoring than expected, negative means more of the runners scored than expected.

Bequeathed baserunners. More simply, the number of runners a pitcher left on base when exiting the game, including runners still on base put there by a preceding pitcher.

Break:Tunnel Ratio - This stat shows us the ratio of post-tunnel break to the differential of pitches at the Tunnel Point. The idea here is that having a large ratio between pitches means that the pitches are either tightly clustered at the hitter's decision-making point or the pitches are separating a lot after the hitter has selected a location to swing at. Either way a pitcher's ratio can be large.

This stat tells us the likelihood that a particular pitch will be called a strike based on a variety of factors. CS Prob is calculated on every pitch thrown by a pitcher. CS Prob is a proxy for control, or the ability of a pitcher to throw strikes.

Deserved Run Average (DRA) uses a collection of multilevel models to estimate the most likely contributions of pitchers to the run-scoring that occurs around them. Unlike other component metrics, DRA considers (and adjusts) for park, opponent, and, when helpful, framing, temperature, and pitch type as well. DRA achieves significant improved reliability over both raw pitcher statistics (like ERA) and other pitcher run estimators. DRA estimates include uncertainty estimates, making it easier to compare players to one another and to appreciate the stability of DRA's estimates, even early on in the season. In general, a pitcher's DRA, plus or minus one standard deviation (DRA_SD) encompasses at least 70% of the "true" DRA values for that pitcher.

DRA-Minus ("DRA–") As noted above, we've received multiple requests for a "minus" version of DRA, something that rates pitchers by how well they compared to their peers rather than by an amount of predicted runs allowed in a given season. Knowledgeable baseball fans are familiar with statistics like this. Common examples include wRC+ and ERA-. The idea is to put an average player for each season at 100, and then rate players by how much they vary from the average. By rating every pitcher by how good (or poor) he was by comparison to his peers, we can make fairer comparisons across different seasons and different eras. These comparisons aren't perfect: We can't make baseball 50 years ago more diverse or force today's players to endure the conditions of 50 years ago, but metrics like DRA– allow comparisons of pitchers across seasons and eras to be much more meaningful.

The formula for DRA-Minus is DRA / DRA_mean * 100

Unlike cFIP (which considers only the three true outcomes), DRA– will not have a forced standard deviation. The two numbers (which are otherwise both scaled to 100) can still be compared, but be mindful of that distinction. For both cFIP and DRA–, lower is better.

See: http://www.baseballprospectus.com/article.php?articleid=26613

Type the definition of the term here, or leave the text as it is if you don't want to add a new term.

Type the definition of the term here, or leave the text as it is if you don't want to add a new term.

Plate Differential - This statistic shows how far apart back-to-back pitches end up at home plate, roughly where the batter would contact the ball. This includes differentiation generated by pitch break and trajectory of the ball (which includes factors like gravity, arm angle at release, etc.).

Release Differential - When analyzing pitchers, we often talk about consistency in their release point, pointing to scatter plots to see if things look effectively bunched or not. This stat measures the average variation between back-to-back pitches at release.

Tunnel Differential - This statistic tells you how far apart two pitches are at the Tunnel Point—the point during their flight when the hitter must make a decision about whether to swing or not (roughly 175 milliseconds before contact).

(from http://bbp.cx/a/26195)

Under baseball’s scoring rules, a wild pitch is assigned when a pitcher throws a pitch that is deemed too difficult for a catcher to control with ordinary effort, thereby allowing a baserunner (including a batter, on a third strike) to advance a base. A passed ball is assigned when a pitcher throws a pitch that a catcher ought to have controlled with ordinary effort, but which nonetheless gets away, also allowing a baserunner to move up a base. The difference between a wild pitch and a passed ball, like that of the “earned” run, is at the discretion of the official scorer. Because there can be inconsistency in applying these categories, we prefer to consider them together.

Last year, Dan Brooks and Harry Pavlidis introduced a regressed probabilistic model that combined Harry’s pitch classifications from PitchInfo with a With or Without You (WOWY) approach. RPM-WOWY measured pitchers and catchers on the number and quality of passed balls or wild pitches (PBWP) experienced while they were involved in the game.

Not surprisingly, we have updated this approach to a mixed model as well. Unfortunately, Passed Balls or Wild Pitches Above Average would be quite a mouthful. Again, we’re trying out a new term to see if it is easier to communicate these concepts. We’re going to call these events Errant Pitches. The statistic that compares pitchers and catchers in these events is called Errant Pitches Above Average, or EPAA.

Unfortunately, the mixed model only works for us from 2008 forward, which is when PITCHf/x data became available. Before that time, we will rely solely on WOWY to measure PBWP, which is when pitch counts were first tracked officially. For the time being, we won’t calculate EPAA before 1988 at all, and it will not play a role in calculating pitcher DRA for those seasons.

But, from 2008 through 2014, and going forward, here are the factors that EPAA considers:

• The identity of the pitcher;
• The identity of the catcher;
• The likelihood of the pitch being an Errant Pitch, based on location and type of pitch, courtesy of PitchInfo classifications.

Errant Pitches, as you can see, has a much smaller list of relevant factors than our other statistics.

In 2014, the pitchers with the best (most negative) EPAA scores were:

And the pitchers our model said were most likely to generate a troublesome pitch were:

Earned Run Average. Earned runs, divided by innings pitched, multiplied by nine.

Uses the same basic framework as a normal quality start - at least 6 innings pitched (or 18 outs) and no more than 3 runs allowed. However, expected runs and outs from fair run average (FRA) are used instead of actual runs and outs.

There is also an adjustment made for a pitcher's level of defensive support, when compared with the seasonal run environment and the park where the game is played.

Fair Run Average in relief appearances.

Fair run average for innings by a starting pitcher. "Fair runs" differ from traditional assignment of runs in that a pitcher who leaves the game is charged with the expected run value of any bequeathed runners left on base, whether or not they eventually score.

FIP is a component ERA inspired by the work of Voros McCracken on defense-independent pitching statistics, but has become more widely used because of the ease of computation - it requires only four easily-found box score stats, uses only basic arithmetic operations and has four easily-memorized constants. It was conceived of by both Tom Tango and Clay Dreslough, the latter of who called it Defense-Independent Component ERA.

At Prospectus, we are including hit batters in the walks term. The constant we use is both league and season specific - in other words, a pitcher in the American League will have a different FIP constant than a pitcher in the National League. This differs from the presentation of FIP on sites such as Fangraphs, which use one constant for both leagues in each season.

Here is an example of the Fielding Independent Pitching spectrum based on the 2011 season:

Fair Run Average differs from FIP in a few ways. While FIP is concerned only with what a pitcher is believed to control-typically strikeouts, walks, and home runs, though Prospectus includes hit batsmen in our FIP calculation-Fair Run Average takes things a step further. Pitchers receive credit for good sequencing, thus rewarding pitchers who seem to work out of jams more often than usual. Fair Run Average also considers batted ball distribution, base-out state, and team defensive quality (as measured by Fielding Runs Above Average).

Here is an example of the Fair Run Average spectrum based on the 2011 season:

Excellent - Clayton Kershaw 2.90
Great - Brandon McCarthy 3.42
Average - Ivan Nova 4.36
Poor - Brett Cecil 5.14
Horrendous - Jake Arrieta 5.88

Fair Run Average Plus is calculated by taking a pitcher's Fair Run Average, dividing it by the league-average, and then subtracting that number from two. The reasoning is provided by Colin Wyers in the Fair Run Average Plus introduction. In addition, park and league quality adjustments are made.

Speed Changes - This is the average difference, in seconds, between back-to-back pitches.

Groundball Percentage. The number of groundballs that a pitcher allows as a percentage of all balls hit into play. Our definition of GB% does not count line drives or popups as groundballs, and considers all batted balls put into play, not just those that result in outs. Because of this definition, the league average GB% is somewhat lower than than what may be listed in other venues, or about 44%.

Hits, or hits allowed.

Not recorded for the NL 1876-1886, the AA in 1882-83, the 1884 UA, and the 1871-75 NA, for either hitters or pitchers.

Hit By Pitch Rate -- HBP per plate appearance

Hit Rate -- hits per plate appearance

Home runs, or home runs allowed.

Home runs allowed per 9 innings pitched.

Home Runs per Inning Pitched

Home Run Rate -- homers per plate appearance

Hits allowed per 9 innings pitched

Hits per inning pitched

While definitions vary, the most common ones credit a pitcher with a "Hold" when he a) enters the game with a lead, b) records at least one out, and c) leaves the game still in the lead.

Not recorded for any league prior to 1955.

Intentional base on balls rate (per plate appearance)

Inherited baserunners.

Total expected run value from inherited runners (runners who are on base when the reliever entered his games).

Number of runners who were inherited by the pitcher (they were on base when he came into the game) and scored while the pitcher was in the game.

Number of runners who were inherited by the pitcher (they were on base when he came into the game) and scored eventually. This includes runners who were on base before the pitcher entered the game and scored after the pitcher left the game.

Innings completed by a pitcher

Inherited runs prevented from scoring. The expected number of inherited runners that would score in the reliever's appearances based upon league average performance, minus the actual number the reliever allowed to score.

Inherited runners who scored. A raw count of the number of runners who scored. This differs from INR, which subtracts INS from the expected number of inherited runners that would have scored given league average performance in the given situations.

Innings Pitched.

Innings pitched as a relief pitcher

Innings pitched as a starting pitcher

The amount of innings pitched as a reliever.

The amount of innings pitched as a starter.

Innings pitched per start.

Inherited runs prevented from scoring. The expected number of inherited runners that would score in the reliever's appearances based upon league average performance, minus the actual number the reliever allowed to score.

A negative number means the reliever prevented fewer runs than average, while a positive number means the relieve prevented more runs than average.

Inherited Runners. The total number of runners on base when the pitcher came into the game.

Strikeouts per 9 innings pitched.

Refers to a pitcher's losses. In context of a team rather than an individual pitcher, refers to team losses.

Total expected run value of all inherited runners still on base when the inheriting pitcher is removed.

95th percentile of velocity among "hard" pitches thrown. These include 4-seam, 2-seam, and cut fastballs ("FA","SI","FC" from Pitch Info, as found on player cards and at Brooks Baseball site).

The number of additional double plays generated versus an average player with the same number of opportunities. Negative NET DP indicates that fewer double plays than average were produced.

Total number of pitches thrown.

Non-Strikeout Out Rate -- batting outs (other than by strikeout, i.e. outs on balls in play) per plate appearance.

On-base percentage. (H + BB + HBP) divided by (AB + BB + HBP + SF). For pitchers, OBP is on base percentage allowed.

Opponent's Quality, Batting Average -- the aggregate batting average of all batters faced (by a pitcher), or allowed by all pitchers faced (for a batter)

Opponent's Quality, On-Base Percentage -- the aggregate onbase percentage of all batters faced (by a pitcher), or allowed by all pitchers faced (for a batter)

Opponent's Quality, On-Base plus Slugging Average -- the aggregate OPS of all batters faced (by a pitcher), or allowed by all pitchers faced (for a batter)

Opponent's Quality, Slugging Average -- the aggregate slugging average of all batters faced (by a pitcher), or allowed by all pitchers faced (for a batter)

Opponent's Quality, True Average -- the aggregate True Average of all batters faced (by a pitcher), or allowed by all pitchers faced (for a batter).

Known outs made by the player or induced by a pitcher, defined by AB-H+CS+SH+SF.

A component of the Pitch F/X dataset, PFX refers to the horizontal movement, in inches, of a pitch thrown. On an individual basis, righthanded pitchers will have negative horizontal movement on a fastball with lefties posting positive numbers. In larger studies, this data is normalized to avoid any type of skewed results.

A component of the Pitch F/X dataset, PFZ is categorized as the vertical movement, in inches, of a pitch thrown. This is often referred to as the rise or sink on a pitch. The greater the number, the more rise. Sinkerballers and those with two-seam fastballs strive for very low PFZ marks.

Number of times picked off

This is the number of sequential pitchers in the sample for the given selection.

This is the selected pitches for drilling down on a specific sequence.

This is the selected pitches for drilling down on a specific sequence.

Percentage of batted balls that were classified as popups (percentage is based on the number of batted balls that were classified at all -- batted balls which do not have a known type are omitted)

PPF is centered around 100, with numbers above and below representing percentage that run-scoring was increased by the mix of parks the pitcher pitched in. For instance, 110 represents 10% above average and 96 represents 4% below average.

Value over Replacement Player (VORP) as a pitcher.

Wins Above Replacement Player (WARP) as a pitcher.

On the custom statistic reports, the Pitcher column is a unique identification number for the respective pitcher.

This stat details the additional called strikes outside the reference zone that are credited to the pitcher after accounting for catcher, umpire, pitch type, etc. This stat is calculated on all called pitches (i.e., balls not in play). Pitcher CSAA is a proxy for command, or the pitcher's ability to locate the ball precisely. Base "CSAA" values are the "expected" or "mean" values for each player. We're now also pleased to provide, for seasons 2008 to the present, the standard deviations (SD) for both CSAA and CSAA / Framing Runs. SDs allow you to calculate uncertainty intervals to say how certain we are that the true measurement of the player falls within the defined interval.

Number of pitches seen (batter) or thrown (pitcher)

Complete statistical data is available for:

• Batters vs left-handed pitchers (LHP)
• Batters vs right-handed pitchers (RHP)
• Pitchers vs left-handed batters (LH)
• Pitchers vs right-handed batters (RH)

Break Differential - This stat tells us how much each spin-induced movement is generated on each pitch between the tunnel point and home plate. Think of this like PITCHf/x pitch movement, except that it is only tracking the time between the Tunnel Point and home plate.

Quality Start: A start where a pitcher completed at least six innings and gave up no more than three runs.

Runs scored (for hitters) or allowed (pitchers).

Relief Percentage -- positive relief decisions (saves and holds) divided by total relief decisions (saves, holds, blown saves)

Runs charged to a pitcher before he is removed from the game (i.e. excluding runners on base when he exited who may have been allowed to score by a subsequent pitcher)

Release:Tunnel Ratio - This stat shows us the ratio of a pitcher's release differential to their tunnel differential. Pitchers with smaller Release:Tunnel Ratios have smaller differentiation between pitches through the tunnel point, making it more difficult for opposing hitters to distinguish them in theory.

Shutouts.

Slugging percentage (hitters) or slugging percentage allowed (pitchers). Total bases divided by at-bats.

Strikeouts. For pitchers, batters struck out, for batters, times struck out.

Strikeout to walk ratio: strikeouts divided by walks.

Strikeouts per 9 innings pitched.

Strikeouts per inning pitched

Strikeout Rate -- Strikeouts per plate appearance

Type the definition of the term here, or leave the text as it is if you don't want to add a new term.

Percentage of pitches thrown for strikes.

Saves.

Strikeouts per plate appearance.

Number of strikes seen (batter) or thrown (pitcher)

Saves + Holds

True Average Against is to True Average what Batting Average Against is to Batting Average. In other words, True Average Against will tell you how well opposing batters have hit a pitcher. Do note that while True Average Against takes the pitcher's park, league, and situational-based hitting into account, it does not exclude data where the pitcher faced an opposing pitcher. Because of that, National League pitchers should possess lower True Average Against than their American League counterparts.

Not recorded for the NL 1876-1886, the AA of 1882-83, the 1884 UA, or the NA of 1871-75.

(from http://bbp.cx/a/26195)

Our hypothesis is that base-stealing attempts are connected with the pitcher’s ability to hold runners. When baserunners are not afraid of a pitcher, they will take more steps off the bag. Baserunners who are further off the bag are more likely to beat a force out, more likely to break up a double play if they can’t beat a force out, and more likely to take the extra base if the batter gets a hit.

Takeoff Rate stats consider the following factors:

• The inning in which the base-stealing attempt was made;
• The run difference between the two teams at the time;
• The stadium where the game takes place;
• The underlying quality of the pitcher, as measured by Jonathan Judge’s cFIP statistic;
• The SRAA of the lead runner;
• The number of runners on base;
• The number of outs in the inning;
• The pitcher involved;
• The batter involved;
• The catcher involved;
• The identity of the hitter on deck;
• Whether the pitcher started the game or is a reliever.

Takeoff Rate Above Average is also scaled to zero, and negative numbers are once again better for the pitcher than positive numbers. By TRAA, here were the pitchers who worried baserunners the most in 2014.

And here were the pitchers who emboldened baserunners in 2014:

Unintentional bases on balls (walks)

Unintentional base on balls rate (UBB per plate appearance).

Unearned Run Average. Equal to (Unearned Runs)/(Innings Pitched)*9

Refers to a pitcher's wins. In context of a team rather than an individual pitcher, refers to team wins.

Perhaps no sabermetric theory is more abstract than that of the replacement-level player. Essentially, replacement-level players are of a caliber so low that they are always available in the minor leagues because the players are well below major-league average. Prospectus' definition of replacement level contends that a team full of such players would win a little over 50 games. This is a notable increase in replacement level from previous editions of Wins Above Replacement Player.

Here is an example of the Wins Above Replacement Player spectrum based on the 2011 season:

Excellent - Jose Bautista 10.3
Great - Hunter Pence 5.2
Average -Gaby Sanchez 2.0
Poor - Adam Lind 0.5
Horrendous - Adam Dunn -1.7

WARP components can be found in this article, which also describes 2015 changes to FRAA: http://www.baseballprospectus.com/article.php?articleid=27944

Walks plus hits allowed per inning pitched.

Whole innings -- complete innings started and finished by the pitcher (no fractional innings are counted)

Wild pitches.

Walks allowed per 9 innings pitched

Winning percentage (wins / total decisions)

Zone Rate is calculated using PITCHf/x data and shows the percentage of pitches seen (by hitters) or thrown (by pitchers) that are in the rule-book strike zone.

Hitter Examples (2012):

Very few: Pablo Sandoval, 0.4005
Few: Kirk Nieuwenhuis, 0.4833
Around average: Andres Torres, 0.5054
Many: Bobby Abreu, 0.5244
Very many: Chone Figgins, 0.5787

Pitcher Examples (2012):

Very few: Jared Hughes, 0.33554
Few: Jared Burton, 0.4775
Around average: Jeremy Accardo, 0.4879
Many: Joe Blanton, 0.5217
Very many: Jake Mcgee, 0.5897

(from http://www.hardballtimes.com/fip-in-context/)

Because cFIP is on a 100 “minus” scale, 100 is perfectly average, scores below 100 are better, and scores above 100 are worse. Because cFIP has a forced standard deviation of 15, we can divide the pitchers into general and consistent categories of quality. Here is how that divides up for the 2014 season, with some representative examples: