3 players who prove why ISO is the most important stat you need to start paying attention to

It's about time that the average baseball fan starts learning more about the advancement and prevalence of sabermetrics -- so why not start with Isolated Power?
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Isolated Power (ISO) is an advanced sabermetric designed to measure a player's raw power, specifically how well they hit for extra bases. It's calculated by subtracting a player's batting average (AVG) from their slugging percentage (SLG), or, more straightforwardly, it can be understood as the average number of extra bases a player earns per at-bat. One of the most beautiful things about this statistic is that it is so simple to calculate -- the formula looks like this:


​The reason ISO is important is that it provides a clear and focused metric for assessing a player's power independently of their batting average. While batting average tells us how often a player gets a hit, it doesn't distinguish between a single and a home run. Slugging percentage, on the other hand, does make this distinction but is still influenced by the player's ability to hit singles. ISO removes the "noise" of singles to concentrate solely on a player's ability to hit for extra bases (doubles, triples, and home runs).

ISO is a critical stat for understanding a player's power, contributing to strategic decision-making and player valuation in baseball. It's a testament to the game's evolving appreciation for detailed analytics in evaluating and maximizing player performance. 

Below are three players that further illustrate why considering ISO is important:

3. Joey Gallo, Washington Nationals

Joey Gallo represents the quintessential power hitter for whom ISO is an especially telling statistic. Known for his home run prowess, Gallo's batting average might not always impress due to the all-or-nothing nature of his hitting approach. However, his ISO numbers are consistently among the highest in the league, highlighting his exceptional ability to drive the ball for extra-base hits.

In 2023, for example, Gallo had an ISO of .262, which would have ranked him 12th in the majors should he have reached the minimum at-bats to qualify. This metric underscores his value as a player who can change the game with a single swing, making him an asset to any lineup, especially in situations where a home run can make all the difference.

2. Cal Raleigh, Seattle Mariners

Cal Raleigh, a less-known player compared to Gallo, presents an interesting case for the importance of ISO. As a player who might fly under the radar based on traditional stats, Raleigh's ISO value can reveal hidden power potential. For catchers, who are often evaluated heavily on their defensive abilities, a strong ISO figure indicates significant offensive contribution.

Last season, Raleigh finished 27th in the MLB with an ISO of .224 — that number really shows that Raleigh has some hidden value as a hitter. This is valuable for teams seeking balanced players who can contribute both behind the plate and in the batter's box.

1. Andrew Benintendi, Chicago White Sox

Contrary to the other two players on this list, looking at Benintendis ISO will show why he is not as valuable as the general public of baseball fans may believe. Benintendi, after a full year of service in 2023, ranked fourth worst amongst qualified hitters in ISO, with a mark of .094.

Although he has a mildly impressive slash line of .262/.326/.256, by seeing his isolated power, you can see why it seems like Benintendi just takes his walks and gets non-impactful singles. By having knowledge of Benintendi's (and similar players’) ISO, you can see why these types of hitters may become overrated/overvalued.

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