Fantasy Fridays: Intro to Stats

Fantasy Fridays

We here at Crush City Station love sports, this includes fantasy sports. This season we will be taking a look at Astros who are fantasy relevant and possibly a few former Stros who make an impact. (George, we miss you already.) So be sure to follow us for our Fantasy Friday articles as the season progresses. 

Over the next two weeks we will be breaking down the projected roster and a few interesting minor leaguers, but since the J2’s will be signing after this posts I thought I would call back to a past writing I did for the Friends With Fantasy Benefits Draft Guide last year. For several years I contributed to their Astros section, last year I also wrote the Intro to Stats. This is that writing. It is a little long, and does break down the basics, but hopefully has at least a little something for everyone. I hope you enjoy it and find it useful.

Intro to Stats

No sport is as attached to measuring itself as baseball is. There are statistics for everything you can think of. Major league teams have entire departments devoted to not only dissecting the stats we have now, but creating new ones that measure aspects of a players game that were not even thought of 30 years ago. 

If you have played fantasy baseball before and want to get into deeper stats, or if you dominated your football league last winter and got pulled into baseball for the first time, this is your place to learn more about the numbers we tend to look at throughout the course of the season. If you are still figuring out the difference between plate appearances and at-bats, or if you want to know what those Statcast and Fangraphs columns mean, read on and hopefully, you will see your ability to analyze players grow.

We will first hit some of the absolute basics, skipping categories like HR, but quickly explaining the difference between things like R and RBI or AVG and OBP. Then we will take a look at some of the MLB Statcast metrics found on the baseball savant page. Then we will dive into the deep end and break down some stats you can find on the Fangraphs website (side note: if you are not using Fangraphs for your player analysis, you are leaving wins/points on the table).

Baseball Basics

So this is your first foray into fantasy baseball. You are a casual fan and know that a .300 average is really good, but don’t necessarily know why a .295 OBP is not. This is the place for you. In this section we will be breaking down a few of the statistical categories you will come across in many if not most fantasy leagues, skipping some counting stats like HR and SB. Those basic statistical categories are usually defined on the web platform you are using. 

This leads me to my first quick definitions. Statistical categories are often referred to as either counting stats (HR, SB, R, RBI, W, QS, Sv, H, K’s) or rate stats (AVG, OBP, ERA, WHIP, K%, K/9). The difference being that the counting stats simply count how many times an event happens, i.e. Babe Ruth hit a home run 714 times. Rate stats are ones in which something is calculated, i.e. Babe Ruth had a career batting average of .342. 

The second quick definition we need to know before going on deals with the difference between an at-bat (AB) and a plate appearance (PA). An at bat happens when a player comes to the plate and gets a hit or an out, so long as that out is not a sacrifice. Sacrifice hits, walks, hit by a pitch, and interferences do not count as an at-bat. A plate appearance counts every time the player comes to the plate.

The most basic reading of baseball stats that has been around for decades is the triple slash, or slash line. It is made up of a player’s batting average, on-base percentage, and slugging percentage. When written down it looks something like this .315/.364/.463 

The first stat we will cover is basic for most and is the first number in the slash line.

Batting average (Avg) is how many hits a player gets per at-bat. This is the standard stat that has been mainstream for over 100 years.

On-base percentage (OBP) is different in that it counts all plate appearances, including walks. If you are playing in an OBP league you need to remember that a player that has a .300 OBP is actually below average because you are counting hits and walks. The MLB average has hovered around .320 for the last decade.

Slugging Percentage (SLG) or sometimes called a players slug is his total bases divided by at-bats. Similar to batting average, except all hits in batting average count as 1 towards the total divided by at-bats, whereas slug counts every base touched by the batter in the hit. Slugging is sometimes confused for a power stat since it requires the ball to get deep in the outfield to garner more bases. However, power is not as important as speed for triples and stretching the occasional single to a double. Meaning it is more of a jumping off point to look at a player’s overall skill set.

ISO is isolated power, or the average of extra-base hits. Usually measured as SLG-AVG.

Runs Batted In (RBI) vs. Runs (R) can be a little confusing for someone new to baseball. It is the number of times a player crosses the plate to score a run. RBI is the runs scored as a result of a player’s at-bat. For example, if player A is on second and player B hits one to far-right field the man on second may score, resulting in an RBI for player B and a run for player A. Now if player C comes up and hits one to left as well then player B can get a run.

An important thing to remember when building your team is that a leadoff hitter may score a lot of runs, but will likely be somewhat limited in RBI since he will either be the first batter of the inning or come up following the bottom of the order. Either way, it is less likely he will have men on base to drive in than others in the batting order.

On the pitching side, we have a few stats that the baseball newby might get a little confused with.

Wins (W) Traditionally, to qualify for a win a starting pitcher must go 5 innings, leave with the lead, and not have the lead lost by the bullpen. With the use of the opener by teams like Tampa Bay this has changed a little, but still mostly holds true.

Quality Start (QS) To qualify for a quality start a starting pitcher must go at least 6 innings and give up no more than 3 runs. 

The difference between the two stats is that QS is not reliant on the team scoring runs, which has made it a popular choice to use as a category in fantasy leagues over the last decade. Of course, with so many starters getting less work in the modern game it can sometimes be frustrating when your guy goes 5 ⅔ innings of scoreless work and gets pulled.

Saves (SV) have been the measure of a reliever for decades and are awarded if a pitcher finishes a game in relief, entering with a lead of no more than 3 and not relinquishing said lead. 

Holds (HLD) are a newer stat we use in fantasy to give middle relievers some more value. The definition of a hold is the same as a save except the pitcher does not finish the game. Most leagues that use holds will just combine them with saves, though more and more we are seeing the category weighted to value saves more, i.e. HLD + SV2 or SV + HLD/2.

Be a Statcast Savant

The modern statistical revolution has gifted us a treasure trove of info we never had before. MLB has a place for some of those new measurements found at, commonly referred to as Statcast, the Statcast page as well as Baseball Savant. The following are some useful stats to look at when breaking down a player or looking to see who is performing well at the moment.

One thing to remember is when you are looking at a graph or chart on Statcast you will notice a color code. Blue means bad and red means good and unhighlighted means average. The darker the color the more extreme.

Many of the Baseball Savant stats are relatively easy to figure out while looking at the charts. A player’s Hard Hit Rate is a measure of how many hits left the bat at or above 95 mph, which is of course good for hitters and bad for pitchers. Others are not quite as straightforward, or at least could use some clarification as to how they can fit into fantasy analysis.

Exit Velocity is one that is pretty straightforward in definition, it is the speed at which the ball leaves the bat. How it affects outcomes is a little different though. Common sense says a hitter wants more exit velocity and a pitcher wants less. However, this doesn’t mean a lighter hitter will have to hit fewer home runs.

In 2019 Victor Robles was dead last among qualified hitters with an average exit velo of 81 mph. Only 14 spots better was Jose Altuve with a light breeze of an 86.1 mph exit velo… and 31 home runs. In the same way more exit velocity does not equal home runs. If Nick Markakis had enough at bats to qualify in 2019, his 91.2 mph average would have made him top 25. All it got him was 9 home runs in over 400 at-bats. The difference comes in part from the next stat.

Launch Angle is at what angle the ball leaves the bat. While the Baseball Savant page gives amazing definitions on what launch angles are and which ones are the best, the dumbed-down version is that there is a goldilocks zone that keeps the ball high enough not to ground out, but low enough not to pop up. 

Barrels is the name of that goldilocks zone. It starts with a ball hit at least 98 mph with a launch angle between 26-30 degrees. As the velocity increases so does the range for acceptable degrees. Barrels have a minimum batting average of .500 and a slugging of 1.500. Why am I telling you this basic definition that the folks over at Baseball Savant have defined themselves? Because it is that important.

Barrels are an amazing tool for a quick rundown of players who are getting great contact. If you are short on time and want to see who is making quality contact this is the place to go. If you want to do some deep research on players, but don’t want to waste time on every Joe out there, this is where you can start.

Sprint Speed can be a tricky stat. It is the average feet per second in the players fast one second of a play. When looking at the chart it is obviously a rank of who has the best wheels. Remember, this does not equate directly to stolen bases. There will always be players who are absolute jackrabbits in the field who are average to mediocre base stealers just as every once in a while there is a guy with no range in the field who can lead his team in steals.

Sprint speed also obviously does not take into account a team’s philosophy on base stealing. If the coach doesn’t send a guy he cant swipe a bag. It can be used as a clue as to why a player may not be stealing as much in a season as it can show if he has lost a step due to age or injury. It also is just fun to look over now and again.

Expected Stats or *Xstats are a useful tool to gauge if a player is over or underperforming in a certain category and are usually designated by placing an x in front of a stat (i.e. xSLG, xERA, xBA). They work by taking in measurements including pitch velocity, exit velo and the like. Then determine what was likely to happen when compared to historical instances that fit the same criteria.

I know, it sounds like voodoo math, but the xstats usually hold pretty close to the real-life averages. For example, in 2019 the MLB batting average was .252 and the expected average was .250. The minuscule difference in batting average and expected average shows that we can predict with some accuracy what the end result should be. 

Sometimes though, a player’s numbers will begin to deviate. If that is the case it is a sign to look deeper. See if a player’s expected average significantly higher than his real average. He could be coming back from a long injury. Scheduling could have forced him to face a couple of ace pitchers with solid defenses behind them recently. That player might be a buy-low candidate. How about when a player’s numbers are reversed? When his real average is dominating his expected numbers it could be a sign that some regression is coming and you may want to trade him while the value is high.

Baseball Savant Statcast numbers are not the only pieces of info needed. However, when looked at as a whole they give a massive picture of why a player is doing what he is doing.

Find it on Fangraphs

First off, I know, a lot of this is not Fangraphs exclusive, but it is a great source to find them all in one place. Second, like on baseball savant, none of these are the stats you will use as categories in your average league. Unless you have accidentally stumbled into some oddball specialty league. They are invaluable to help sift through players who are underperforming, overperforming, about to break out, or close to cratering.

A couple of these first few stats you may know. We will go over them though, as they will be needed for the rest of the stats.

BABIP stands for Batting Average of Balls In Play, or the batting average of only the balls hit into the field of play. Everything from strikeouts to home runs are not counted in BABIP. Only batted balls which have to be fielded. To oversimplify things, BABIP can be used as a measure of luck.

When you see a player with an outlier number, up or down, it is likely they will show some regression back towards the mean. There are some exceptions that make BABIP not the end-all of luck. For instance, an incredibly speedy player can have a higher BABIP since his wheels allow him to outrun an infield hit. While babip can show if a player has been lucky, it is not a strictly luck stat

For pitchers, BABIP can show when a pitcher has had some bad luck in the field, inflating his ERA and giving hope of some positive regression. On the other hand, it may mean he is pitching in front of a horrendous defense and has less room for improvement. 

BACON stands for Batting Average on Contact. So, it’s BABIP, but with home runs added. I like to say BACON makes everything better, and for the hitter it does. A player like Judge or Stanton will hit enough home runs over the course of a healthy season to significantly outpace their BABIP. The same goes for some pitchers who like to give up the long ball. Both units have their place in research though. 

wOBA is the Weighted On Base Average. It combines the aspects of a plate appearance in a weighted format. To oversimplify, it takes the components of the triple slash and combines them according to impact on run values (another can of statistical worms we will not cover in this chapter). Basically, imagine a somewhat better barometer of a hitter than just batting average or OBP alone, making it a good tab to sort by when starting your research.

wRC+ stands for Weighted Runs Created Plus. The simplest way to understand it is take wOBA and add in park factors making an even more precise number. wRC+ works on a scale with 100 being league average.

GB%, FB%, LD% refers to the percentage of Ground Balls, Fly Balls, and Line Drives a player hits. Generally speaking, a player doesn’t want to many ground balls unless he is a speedster that can beat the throw to first. In the same way, a player doesn’t want to many fly balls unless he is a masher that can get it out of the park. Line drives are the sweet spot that usually produces the best batting averages for all types of hitters.

For pitchers, These rates basically work in reverse. You do not want to see your pitcher with a high line drive rate. That will raise WHIP and ERA. The best thing for a pitcher is to have a high GB%. That will suppress the ISO he gives up as well. Some pitchers can live with a high FB% if they are also good at suppressing their HR/FB rate.

GB/FB is the rate of Ground Balls hit to Fly Balls. This useful tool gives you a  look into players who can get the ball in the air, meaning more chances for home runs. The caveat to this is some players who normally have warning track power have been trying to lift the ball more since the ball has changed, resulting in some crazy power spikes. GB/FB rates over the course of the last several seasons may help you to know why a player has spiked, and possibly identify players who could spike if they just adjust their rate.

For pitchers, you really want to see a higher rate of ground balls as it will limit extra-base hits, including home runs.

HR/FB is the rate at which a player’s Fly Balls turn into Home Runs. The top power hitters in the game usually have rates around 25% and up. Sometimes, there is a worry that players with high percentages are due for regression. 

However, you also have to take into account possible changes in the ball and a change of scenery. Christian Yelich had a spike when he moved from Miami to Milwaukee. This makes total sense though as Miami is a noted pitchers park that suppresses home runs.

Jose Altuve had a massive spike this year, going from a career average of 9.5% to 23.3%. He is an example of a player you would want to look deeper into to why this spike happened. 

For pitchers, this is an important number. Some pitchers have a skill at suppressing home runs. They can give up more flyballs, but turn them into pop-ups. Although, it should not be assumed that a pitcher with a high HR/FB is a bad pitcher.

IFFB is the In Field Fly Ball rate. You do not want your players high on this list. It is the measure of how often a player pops up to the infield. Here are guys who need to lower their launch angle because an infield fly is as bad as a strikeout. Also, remember when we talked about players who may have a low babip regressing back up to their peers? A player with a high IFFB rate is not as likely to have that positive regression as they are giving up too many easy outs.

For pitchers it’s simple. You want infield fly balls as they are simple pop-ups that are almost a guaranteed out.

Pull%, Cent%, Opp% are references to a batter’s directional tendencies when he makes contact. Normally, it is easier to hit a home run to the pull side. However, guys that hit that way too much are often candidates for defensive shifts.

For pitchers, this can help show if he has an exaggerated lefty/righty split. This could be useful if a pitcher has a game against a team he might not be able to handle. That gives you the opportunity to bench him for a better option. It could also hint his defense let him down and a need for the manager to tinker with the shift.

Soft%, Med%, Hard% refers to the quality of contact for a hitter as measured by hangtime, trajectory, and landing spot. These Fangraphs metrics do not take into account exit velocity. However, they are still a great tool for finding a good hitter. Especially one who’s babip may actually be just bad luck. As a general rule, you want more Hard% and less Soft%. 

For pitchers, it is kind of obvious. The softer the better. A pitcher who allows more hard contact will usually have a higher HR/FB rate and BABIP. He will not necessarily regress back down.

O-Swing% & Z-Swing% refer to percentages of swings at pitches outside of the zone (O) and inside the zone (Z). Obviously, it is better to lay off pitches outside of the zone and to swing at pitches inside the zone. These numbers are better at looking back than they are looking ahead. However, if you have a guy going through a slump you can look back and see if there have been changes. Conversely, if a mediocre guy is hot, you can see if it is sustainable or a flash in the pan.

For pitchers, a swing out of the zone is usually good. It means the pitcher is getting batters to chase pitches that aren’t usually hittable. Generating swings in the zone could go either way. A pitcher could be fooling guys with deceptive movement, or he could just be tossing in cantaloupes.

O-Contact% & Z-Contact% is the percent of times contact is made one the swings mentioned above. Very similar in usefulness to the swing numbers. However, it can also highlight a batter who has that odd knack for hitting the outside pitch. Which doesn’t make him more valuable, but makes a high O-Swing% less detrimental.

For pitchers contact out of the zone is usually good as pitches out of the zone are often times harder to make good contact with, generating fouls, ground balls, and pop-ups. So a high O-contact can sometimes be a good thing.

Contact in the zone usually means you are giving up hits of some kind. Yes, a good pitcher can still induce weak contact in the zone, so be sure to look at that. However, as you will see in a simple search, there are not many good pitchers with a high rate. In 2019, the top 20 highest O-contact rates had only 4 pitchers below a 3.50 ERA. Another 3 had ERA’s over 5.00

FIP is Fielding Independent Pitching, which is an attempt to measure ERA based solely on things the pitcher does. It takes into account hit by pitch, walks, strikeouts, and home runs and ignores all other outs and hits. The goal being to see what happened when the pitcher was responsible for the outcome. FIP can help compare a pitcher’s “true talent” to his ERA.

For example, Jose Quintana had a 4.68 ERA in 2019 versus a 3.80 FIP. You may want to look deeper at his games and the defense around him. It may point some positive regression ahead. On the other side of the coin, Mike Soroka posted a 2.68 ERA and a 3.45 FIP. You would want to look deeper to see if he was the beneficiary of defense or luck or something else. That may cause him to regress to a higher ERA in the coming season.

SIERA stands for Skill Interactive ERA and is similar to FIP in that it tries to find a pitchers true talent ERA, but different in that it also tries to limit park factors and allows for some batted ball data. Here, pitchers who have higher GB% and FB% will get a bump as these skills usually lead to quicker outs.

K/9, BB/9, H/9, HR/9 are all pretty obvious. They are the rate of Strikeouts, Walks, Hits, and Home Runs per 9 innings accumulated by the pitcher. You want K to be as high as possible and the rest to be as low as possible. A pitcher with a high K rate will not only affect strikeouts, but it will also suppress ERA and WHIP. On the same token, high numbers in the other three stats will inflate ERA and WHIP.

K% & BB% are the percentage of Strikeouts and Walks a pitcher earns. Very similar to the per 9 in its use for fantasy, expressed as a percentage of the whole instead.

K/BB is the ratio of strikeouts to walks for the pitcher. This direct comparison of non-batted ball outcomes is a good indicator of control for a pitcher.

WAR is an all-encompassing number that stands for Wins Above Replacement. It is a backward-looking attempt to quantify every aspect of a player’s game. WAR can be really fun to sort by, but at best it has near-zero value in fantasy player evaluation. It would be easier to look at top 500 fantasy player lists that will have as much value as WAR. If not much more. If you are paying attention enough to read this, then you are paying attention enough to ignore WAR.

I hope that this has helped you to understand some of the mountains of information available to you. As well as to understand what someone is saying in anarticle or on a podcast. Always ask if you come across a stat that is not listed above and get confused. Reach out to any of us at Crush City Station and we would love to help.

Don’t miss out on Astros news and notes here at Crush City Station. Read our article on Cheo Cruz in Know Your Stro. Lets Go Stros!