Fantasy Baseball 101: Fantasy baseball glossary

Fantasy terms

Auction draft: A style of fantasy baseball draft in which every manager is given a budget of money to fill his or her roster. Players are nominated and bids are placed, with the highest bidder earning each player until every roster is filled. This is a format available in ESPN League Manager leagues, and in the Live Draft Lobby.

Average Draft Position (ADP): This is the measure of which position a player is being drafted, on average, in all ESPN Live Drafts. So, for example, in 10-team leagues, consensus first-round picks will have an ADP of 1.0-10.0, but due to difference of opinion from drafters, there may be fewer than 10 players who actually end up with an ADP in that range.

Corner Infield (CO): This is a standard lineup spot in fantasy baseball which can be filled by any player with eligibility as either a first baseman or a third baseman.

Dynasty: A format of fantasy league in which managers keep most or all of their players from year to year, acting more like "real-life" general managers by building up a franchise and playing to win now -- or win later. This differs from a "keeper league," which often involves holding onto players year over year, but typically involves fewer players kept per manager. Either way, the general concept is the same: Your decisions require more of a long-term mindset as multi-year value is a consideration.

Free Agent Auction Budget (FAAB): Certain leagues will opt for a system of picking up players that involves spending dollars from a set budget to bid against others in the league. Players who are available on waivers will be open for bidding, and the manager who places the highest bid will have that player added to his/her roster. This is a custom setting that can be employed in ESPN League Manager leagues.

Middle Infield (MI): This is a standard lineup spot in fantasy baseball which can be filled by any player with eligibility as either a second baseman or a shortstop.

Snake: A draft format for fantasy baseball defined by a back-and-forth pick order by round. Using the example of a 10-team league, the first round will go from one to 10, with the player picking 10th immediately picking again at 11, all the way back to the player who picked first picking again at 20 and 21. This ensures that those who draft late in the first round get better picks in the next round, while those lucky enough to get the top pick have to wait for their next player. This is the most common draft style in fantasy sports, and is available in the ESPN Fantasy Baseball Live Draft Lobby.

Utility (UT): This is a standard lineup spot in fantasy baseball which can be filled by players with any positional eligibility, other than pitcher. If a player only has eligibility as a designated hitter (DH), then this is the only lineup spot in which he can be utilized.

Waivers: A common system in fantasy leagues in which players are placed on hold as free agents, allowing multiple teams to attempt to claim the player and add him to their roster. Waivers allow fair access to players who might be coveted by multiple managers, and avoids a free-for-all system which simply awards the person who is quickest to add a player to his or her team. Waivers are awarded differently in most leagues, so be sure to check your league settings to see how waivers work for your specific league.


Batting Average Against (BAA): Also called OBA or opponent's batting average, this is simply the total batting average of all hitters who have faced an individual pitcher. The formula: It's not as complicated as it seems as it's hits allowed divided by total batters faced, less any walks allowed, hit-by-pitch, sacrifice bunts/flies and catcher's interference. Anything below .255 is better than league-average in this category.

BABIP, or Batting Average on Balls In Play, was invented by Voros McCracken in 1999 and is typically used to measure the impact of luck on a hitter or pitcher's batted balls put into the field of play (and not over the wall). Specifically, it calculates a hitter's batting average or pitcher's batting average allowed on any non-walk, strikeout or home run outcome. If we're talking about BABIP, most likely we're doing so as a way of demonstrating how a certain player was either extremely or unlucky during a given time, though a player's quality of contact does influence his performance in the category. The major league average for BABIP is generally about .300, which is exactly where it resided in 2017, though it can vary slightly depending upon whether your source includes or excludes sacrifice flies. For our purposes, we include them. The formula: Hits minus home runs, divided by at-bats minus home runs minus strikeouts plus sacrifice flies -- or (H - HR)/(AB - HR - K + SF).

Barrels: Created by Tom Tango and a Statcast measure only implemented league-wide as recently as 2015, Barrels, per MLB.com's own glossary, are "assigned to batted-ball events whose comparable hit types (in terms of exit velocity and launch angle) have led to a minimum .500 batting average and 1.500 slugging percentage." A Barrel requires an exit velocity of at least 98 miles per hour with a launch angle between 26-30 degrees, though the launch angle expands with each additional mile per hour over 98. The measure is designed to identify players with greater natural power than others, and can also be used as a rate statistic, calculating it as a percentage of batted-ball events or plate appearances.

Chase Rate: This measures a hitter's rate of swings at pitches that ESPN's pitch-tracking tool judges as outside the strike zone, or a pitcher's rate of inducing hitters to "chase" such non-strikes. It's a more useful tool on the hitting side, where it can identify particularly patient or impatient players, though it can also reveal a pitcher's deceptive ability or quality of movement on his pitches. Joey Votto swung at 14.0 percent of non-strikes in 2017, while Salvador Perez chased such pitches 47.2 percent of the time.

Contact Rate: Somewhat self-explanatory, it measures a hitter's frequency of making contact and putting the ball into play. This statistic is most useful for determining a hitter's batting-average potential, as those with higher contact rates typically hit for higher averages. The major league average in the category can fluctuate, especially across different eras, especially recently as the league's overall strikeout rate has risen dramatically. In 2017, the league's average Contact Rate was 77.9 percent. The formula: At-bats minus strikeouts divided by at-bats -- or (AB - K)/AB.

Exit Velocity: Measured primarily by Statcast, Exit Velocity measures the speed of the baseball after it is struck by the hitter's bat in miles per hour, regardless of the outcome of the play. It can be averaged over any span of time, and split up by any type of batted ball, though most commonly fly balls and line drives, and helps identify hitters with greater quality of contact -- or pitchers who suppress it more -- than others.

Fielding Independent Pitching score (FIP): Similar to ERA, and calculated on an ERA scale (with comparable ranges of success or failure), Fielding Independent Pitching evaluates only the events upon which a pitcher has the most control -- strikeouts, walks, hit batsman and home runs -- extracting results on balls hit into the field of play in order to strip "luck" from the equation. Pitchers who have unusually high or low FIPs compared to their ERAs might have gotten good or bad breaks, respectively, though the pitcher's defense, ballpark and other factors might well have contributed to his ERA result. The formula: Home Runs times 13 plus Walks plus Hit Batsmen times 3 minus Strikeouts times 2, divided by Innings Pitched, plus a FIP constant (dependent upon that season's run environment), or ((HR * 13) + (BB + HB) * 3 - (K * 2))/IP + FIP constant. The FIP constant formula: MLB ERA - ((MLB HR * 13) + (MLB BB + MLB HB) * 3 - (MLB K * 2))/MLB IP.

Ground Ball-to-Fly Ball Rate (GB/FB): You've probably heard the phrase "ground-ball hitter" or "fly-ball pitcher." This is a simple statistic that puts an actual number to these designations. The stat in of itself doesn't have any direct correlation to a player's fantasy value, but can be useful in analyzing why a player is performing the way he is. However, pitchers who have a high GB/FB rate will rely more heavily on their team's defense in order to have success. Pitchers with a low GB/FB rate who pitch in a ballpark with short fences will be far more susceptible to the longball. Similarly, a batter with a ton of speed and a high GB/FB is more likely to be able to leg out some hits than a similar player with a low GB/FB.

Home Run per Fly Ball Rate (HR/FB%): Another measure commonly used to identify a player's penchant for luck, Home Run per Fly Ball Rate, unsurprisingly, measures the percentage of a player's batted balls in the air that clear the fence. This is most useful on the pitching side, where pitchers have less control over whether a fly ball clears the fence or only makes it to the warning track, though it can also identify annual outliers on the hitting side. As with BABIP, a hitter's quality of contact can have great influence on his Home Run per Fly Ball Rate. There is also a bit of debate as to the formula, as FanGraphs' measure tends to be more liberal with classifying batted balls as line drives, resulting in higher Home Run per Fly Ball Rates than ESPN's pitch-tracking tool, while the latter includes pop-ups in the denominator. This is why FanGraphs' league average in 2017 was 13.7 percent, while our pitch-tracking tool had it at 10.6 percent. The formula: Home Runs divided by Total Fly Balls, or HR / FB. Pop-ups can also be added to the denominator.

Isolated Power (ISO): This measures a hitter's raw power, as it only rewards extra bases earned on extra-base hits -- as in the extra base for a double, two extras for a triple and three for a home run. Hitters who excel in this category tend to fare well in the "power"-based Rotisserie categories like home runs and RBIs. The major league average for Isolated Power in 2017 was .171. The formula: Doubles plus triples times two plus home runs times three, divided by at-bats -- or (2B + (3B * 2) + (HR * 3))/AB. Isolated Power can also be calculated by subtracting batting average (BA) from slugging percentage (SLG).

Launch Angle: Another Statcast measure, Launch Angle measures the vertical angle at which a batted ball leaves a hitter's bat. It is most commonly averaged across all of a player's batted ball events, and can easily measure the type of batted ball in play. Ground Balls typically have Launch Angles less than 10 degrees, Line Drives have Launch Angles between 10-25 degrees, Fly Balls have Launch Angles between 25-50 degrees and Pop Ups have launch angles greater than 50 degrees, per MLB.com.

Left On Base Percentage (LOB%): Sometimes referred to as Strand Rate, this measures a pitcher's ability to prevent runners he allowed to reach base from scoring. Extreme variances from the league average can be interpreted as luck taking effect, though it's often as likely that bullpen support, defense or a pitcher's propensity for home runs or difficulty pitching out of either the stretch or windup is responsible. Jeff Samardzija is one pitcher who historically has had trouble stranding men on base (69.6 percent left on base percentage from 2007-09), while Lance Lynn has been exceptional at doing so (79.0 the past three years). The major league average for left on base percentage is generally about 72 percent, and in 2017 was 72.6. The formula: Hits plus walks plus hit batsmen minus runs, divided by hits plus walk plus hit batsmen minus home runs times 1.4 -- or (H + BB + HB)/(H + BB + HB - (HR * 1.4)).

OPS: A popular statistical tool since the turn of the century, OPS is a player's On-base Plus Slugging percentage, or the combined total of his numbers in those two categories. Typically speaking, the best players in baseball tend to rank among the leaders in OPS. It can, however, be somewhat misleading, as a player who had an especially high on-base percentage or slugging percentage, but not both, might look equally skilled to the one whose strength was the opposite. It's for that reason many of our player profiles list the aforementioned AVG/OBP/SLG, instead of straight OPS, in order to give you a greater sense of skill sets.

Quality Start (QS): While wins are the name of the game in real baseball, and many fantasy Rotisserie leagues still use wins as a category, it's long been concluded that it's a lousy metric for determining the overall quality of a pitcher. That's where this stat comes in. Coined by John Lowe in 1985, a starting pitcher can be considered to have thrown a quality start when he retires at least 18 hitters (six innings) and allows three-or-fewer earned runs in the process. While doing the minimum required for a QS would result in a rather mediocre 4.50 ERA, the stat nevertheless is catching on as a far better metric than wins in terms of pitcher valuation.

Runs Created (RC): Invented by Bill James, this is a statistic used to measure how many runs an individual player's production has been directly responsible for. Generally speaking, when you add up the RC of all players on an individual MLB team's roster, you'll get an approximation of how many runs that club has actually scored. The formula: While there are several different version of the calculation, the one ESPN uses is [(H + BB + HBP - CS - GIDP) times (Total bases + .26[BB - IBB + HBP] + .52[SH + SF + SB])] divided by (AB + BB + HBP + SH+ SF)

RC/27: While RC helps you approximate what percent of an MLB team's runs can be directly attributed to an individual player, RC/27 is a way to better help compare players from different teams by coming up with a hypothetical value of what a team made up of nine "clones" of an individual player would be expected to score over a nine-inning game with 27 outs.

Slash Rates, sometimes referred to as Triple Slash Rates or Hitting Rates, represents a hitter's set of three hitting ratios, batting average (AVG), on-base percentage (OBP) and slugging percentage, (SLG) in order to profile a fuller picture of the player's strengths, weaknesses and natural hitting ability. In many of our profiles we list a hitter's Slash Rates or Triple Slash Rates in all three categories, such as Charlie Blackmon's .348/.429/.627 second-half numbers.

Steals Rate: It's not a readily available statistic, but can be calculated using numbers available on Baseball-Reference.com. This is the percentage of a player's stolen-base attempts compared to his total number of opportunities. Steals rates can help identify players who might have lost a step, players who have improved their ability to read opposing pitchers on the base paths, or managers who like to employ the steal more than others. The formula: Stolen bases plus times caught stealing, divided by stolen base opportunities (which can be found on the aforementioned Web site) -- or (SB + CS)/SBO.

Strikeout Rate and Strikeouts Per Nine Innings Ratio: These are two measures of a pitcher's ability to strike out opposing hitters, and the former can also be used for hitters to measure their frequency of striking out. Strikeouts Per Nine Innings Ratio has more commonly cited historically, though Strikeout Rate, which calculates strikeouts as a percentage of a pitcher's total batters faced rather than outs recorded -- innings pitched being a measure of a pitcher's number of outs recorded, which is innings pitched times three -- provides a fairer representation of his true strikeout potential. It also affords the ability to measure hitters and pitchers on the same scale. In this strikeout-rich era, a good Strikeout Rate is at least 25 percent for a pitcher and beneath 20 for a hitter, while a good Strikeouts Per Nine Innings Ratio is at least nine (or one K per inning pitched). The formulas: Strikeout Rate is Strikeouts divided by Total Batters Faced (pitchers)/Plate Appearances (hitters), or K / TBF (pitchers) and K / PA (hitters). Strikeouts Per Nine Innings Ratio is Strikeouts times 9 divided by Innings Pitched, or K * 9 / IP.

Strikeout-to-Walk Rate (K/BB): Simply the number of strikeouts a pitcher has recorded, divided by his number of walks allowed to produce a single number. This is particularly useful in points-league formats as a determinant of success, as pitchers earn extra points for strikeouts, but lose points for bases-on-balls. A K/BB lower than 3.00 is going to be very hard for a starting pitcher to overcome in order to return value in that format.

Swinging Strike Rate: Another way to evaluate a hitter's propensity for outright swings and misses or a pitcher's ability to generate them, Swinging Strike Rate measures a player's outright misses on all pitches he sees or throws. Different from Strikeout Rate (K%), this measures all pitches rather than only plate appearance-deciding offerings, and can often provide insight as to whether a player's Strikeout Rate might've been sustainable. The formula: Swings and Misses divided by Pitches Seen/Thrown.

Walk-to-Strikeout Rate (BB/K): This is essentially the same stat as K/BB, but for hitters - although you will also often see it presented in the same K/BB form, using BB/K is preferred so that you can eliminate confusion as to what value you should be looking for in this statistic. Again, hitters gain points from walks and lose them from strikeouts, so for points leagues, the closer this number is to 1.00, the more valuable a hitter will be. Anything under 0.33 is going to all but eliminate a huge chunk of the points that result from a power hitters' extra-base hit totals.

Weighted On-Base Average (wOBA): Created by Tom Tango and described as a better way to measure a hitter's overall offensive value, Weighted On-Base Average combines all aspects of hitting -- singles, doubles, triples, home runs, walks, unintentional walks and times hit by pitch -- and weights each in proportion to how much the outcome contributes to a team's chances of scoring runs. The formula varies by year depending upon how valuable each of those outcomes in said season, and gives a clearer overall picture of a player's hitting contribution. The league's average wOBA varies significantly by era, typically landing within range of .335 historically, though in recent years has fallen beneath that number. In 2017, the league average was .331. The formula: Unintentional Walks times 0.69 plus Times Hit By Pitch times 0.72 plus Singles times 0.89 plus Doubles times 1.27 plus Triples times 1.62 plus Home Runs times 2.10, divided by At Bats plus Walks minus Intentional Walks plus Sacrifice Flies plus Times Hit By Pitch, or ((uBB * 0.69) + (HBP * 0.72) + (1B * 0.89) + (2B * 1.27) + (3B * 1.62) + (HR * 2.10))/(AB + BB - IBB + SF + HBP), where the multipliers can increase or decrease depending upon the league's run environment in the given season.

Well Hit Average (WHAV): Tabulated by ESPN's internal pitch-tracking tool, Well Hit Average calculates a hitter's rate of making hard contact -- in this case such batted balls are called "Well Hit" (WH) -- or a pitcher's rate of suppressing it. Hitters with higher rates in the category tend to have higher-quality offensive stats, whether batting average, home runs or both, while those with lower rates tend to be weaker hitters. Pitchers who surrender higher rates in the category tend to have weaker stuff, while those with lower rates tend to have better stuff. In the nine seasons for which we have data, the league average in the category has ranged from as high as .215 (2011) to as low as .150 (2016), but in 2017 it was .162. The formula: Well Hit, divided by At Bats plus Sacrifice Flies, or WH/(AB + SF).

WHIP, or Walks plus Hits divided by Innings Pitched, is a Rotisserie Baseball innovation created by Daniel Okrent, the game's creator, in 1979, though at the time he called it "Innings Pitched Ratio." It is one of the most common statistics used in categorical fantasy baseball leagues and provides a rough estimate of the number of baserunners a pitcher allows. Pitchers with a WHIP beneath 1.000 are considered extraordinary in the category; those with greater than 1.350 are generally considered mediocre or worse. The formula: It's rather self-explanatory, Walks plus Hits divided by Innings Pitched, or (BB + H) / IP.

Wins Above Replacement (WAR): This player-valuation measure uses sabermetric principles in an attempt to summarize all of a player's contributions to their team -- hitting, pitching, fielding and baserunning -- into one statistic. WAR essentially attempts to answer the question, "If the player in question were to get injured and their team had to summon a replacement from either their bench or the minor leagues, how much value, in team wins, would it lose?" For example, a player with 2.5 WAR would be considered worth 2 ½ wins to their team in the given season, while a player with minus-2.5 WAR would be costing their team 2 ½ wins. There are different formulas for WAR, however, which often causes debate about the category. FanGraphs, whose calculation is often called fWAR, is one, while Baseball-Reference.com, whose calculation is often called bWAR, is the other and ESPN's standard for the category.

xFIP, or Expected Fielding Independent Pitching, is similar to FIP, except that instead of taking a pitcher's total Home Runs allowed, it assumes a league average Home Run per Fly Ball Rate. The formula: The same as FIP, except that Home Runs in the (HR * 13) portion of the numerator becomes Fly Balls times the MLB Home Run per Fly Ball Rate times 13, resulting in ((FB * MLB HR/FB% * 13) + (BB + HB) * 3 - (K * 2))/IP + FIP constant.