Baseball Savant is one of the most useful tools for die-hard baseball fans to study player analytics and check how players are doing. It’s a great set of metrics that baseball fans and statheads like me love. However, many people are overwhelmed by the sheer amount of data on the Baseball Savant page or simply look at the famous red or blue balloons to see how good a player is. Because diving headfirst into a Savant page for the inexperienced can be intimidating, I’ve written the first part of a two-part guide on how to properly analyze a Baseball Savant page and separate the useful information from the eyewash. This edition focuses on hitters. Part two will discuss pitchers.
There is a lot of information about Baseball Savant, but it gets pretty complicated. To keep things simple, this guide only focuses on the main graphics on an individual player’s Savant page, which are the most basic graphics that Savant users typically use and are illustrated in the section below.
The Bubbles
The most popular part of the players’ Baseball Savant page are the bubbles you see when you first open the page. A screenshot of this balloon graphic is prime evidence for any type of Twitter argument. For those who don’t know, bubbles are a series of percentage ratings in various statistics. The higher the percentage, the better that player is at that stat. These bubbles also have an associated color on a gradient between dark blue and dark red as a visual aid to make them easier to read. Blue means lower percentage ranks and red means higher. Here’s a sample of Jordan Alvarez’s bubbles so far through the 2024 season.
A lot of metrics are thrown into that one graphic. Here are the explanations for all of them.
Value
The bubble graphic starts with three stats of value: Batting, Baserunning, and Fielding. They are easy to understand. measure the number of runs added or subtracted by a player. A positive value of 5 indicates a gain of 5 runs, while a value of -5 means that the player has lost 5 runs. This stat is similar to WAR in that they provide a single number to measure a player’s overall value, but it is broken down into three aspects: batting, fielding, and baserunning. Value is a quick and easy way to see everything a player brings to a team between different aspects of the game.
Batting:
The hitting section of the Baseball Savant page is the most extensive and most frequently used section when analyzing hitters. The section begins with three expected stats: xwOBA, xSLG, and xBA. All of these expected stats use Statcast data that tracks bat-ball speed and launch angle to estimate the probability of each batted ball being a hit or an out. Those probabilities are then used to form what a player’s stats (wOBA, SLG, and BA) are “expected” to be, forming xwOBA, xSLG, and xBA. xwOBA (and all expected stats) is more nuanced than conventional versions and removes the influence of luck on player evaluation. A player with a high xwOBA but an actual low wOBA can have some bad luck, while a player with a low xwOBA but an actual high wOBA usually has some success. This same principle also applies to xBA and xSLG.
Next is the average output speed. This is simply the average of all the exit velocities of the balls hit by the player. This is a useful metric because the harder a player hits the ball on average, the better the player usually performs over a large sample size.
The next three statistics used are the three quality of contact statistics. Barrel%, Hard-Hit% and Sweet-Spot%. Barrel is classified in the analytics world as the optimal combination of exit velocity and launch angle on a hit ball. Barrels usually result in a well-hit ball that has a high probability of positive offensive outs, such as extra-base hits or home runs. Barrel% is the percentage of balls hit that are barreled. Hard-Hit% is the percentage of balls hit that were hit hard (exit velocity greater than 95 mph). The last of these metrics is the Sweet-Spot, which measures the rate at which a hitter makes contact with the ball in this optimal zone (the “sweet spot”), compared to the total number of times they hit the ball. Hitting the sweet spot is defined as creating a launch angle between 8 and 32 degrees on the ball. These three statistics are valuable metrics for evaluating the quality of a hitter’s contact and predicting their offensive performance. Higher quality contact usually leads to more power and better results at the plate, while poor contact is usually indicative of ineffective hitting.
The last grouping in the batting section is Chase%, Whiff%, K% and BB%. Chase, also known as O-Swing% (Swings on Pitches Outside the Strike Zone), measures the rate at which a hitter is, well, swinging at pitches outside the strike zone. A high Chase% indicates that a hitter has poor discipline, which can lead to more strikeouts and fewer walks. It indicates that a hitter is either easily fooled by pitches or struggles to delay pitches that are not hitable. Conversely, a lower Chase% indicates that a hitter has better plate discipline and is more selective about the pitches they swing at, which can lead to more favorable counts, better hits, and ultimately bigger hits. of success. Whiff, also known as Swinging Strike Percentage or Swing and Miss Percentage, measures the rate at which a hitter swings and misses at pitches. Whiff% gives an idea of ​​a hitter’s ability to make contact with pitches. A high Whiff% suggests that a hitter is having trouble making contact and may have holes in the swing or difficulty recognizing pitches. Conversely, a lower Whiff% indicates that a hitter is making more consistent contact with pitches, which is generally associated with better hitting ability and a lower strikeout rate. Finally, K% and BB% simply show the percentage of at bats that end in a K or BB. These metrics are better than the cumulative number of Ks or BBs because they can normalize it for players with different amounts of PAs.
Fielding
Next up are the three fielding stats: OAA, Arm Value and Arm Strength. OAA (abbreviated as Outs Above Average) is one of the most important defensive statistics. OAA is based on tracking data often provided by Statcast in Major League Baseball. This data shows the initial direction, speed and hang time of each ball, as well as the position and reaction of the fielder. Using this tracking data, the expected outcome is determined for each ball hit based on the aforementioned factors. For example, a well-struck line drive with a low launch angle has a high chance of becoming a hit, while a weakly-struck pop has a high chance of being caught. The OAA compares the fielder’s actual performance to these expected results. If the umpire plays a more difficult game than average based on the expected result, he is assigned an “Above Average” rating. Conversely, if they can’t make an easier-than-average play, they can stand for it. This is the best defensive state we have access to at the moment. The last two stats, arm value and arm strength, are both used in added runs value. They simply measure the effect of a player’s hand on the game. A positive trigger value indicates a plus arm, and a negative value indicates a bad arm. They are not used as much as OAA or as important, but still provide useful insight.
Running
The running section only has one stat, Sprint Speed. Sprint Speed ​​is measured by Statcast, a high-speed tracking technology installed in all MLB stadiums. Statcast captures the time it takes a player to run from the time the ball is hit, or the player starts running, depending on the context, to a certain point on the field. This time is then converted to a velocity measurement in feet per second. The specific distance traveled varies depending on the situation being measured. For example, when measuring a player’s running speed on the base paths, it might be the distance between two bases. When measuring a player’s outside defense, it can be the distance traveled to make a catch. Sprint Speed ​​can provide insight into a player’s performance and development over time. Changes in Sprint Speed ​​values ​​can indicate an improvement or decline in a player’s physical abilities. Overall, Sprint Speed ​​is a useful metric for quantifying a player’s speed and athleticism in baseball, providing valuable insights for player evaluation, performance analysis, and strategic decision-making.
Understanding and effectively analyzing the data presented on the Baseball Savant page is a valuable skill. While the sheer amount of information available can seem overwhelming at first glance, breaking down each component allows for a deeper understanding of a player’s performance and contribution to the game. The balloons, with their percentage ratings and color-coded visuals, provide a quick snapshot of a player’s overall value and performance while batting, batting and fielding. These metrics, such as expected stats, contact quality, and plate discipline indicators, provide insight into a player’s skills beyond traditional stats like batting average or fielding percentage.
