What is Fielding Independent Pitching in Baseball?

Baseball, often hailed as a game of numbers and statistics, continues to evolve with the advent of advanced analytics. One such metric that has gained prominence in evaluating pitcher performance is FIP, or Fielding Independent Pitching. If you’ve ever wondered about the significance of FIP and how it influences the understanding of a pitcher’s effectiveness, this guide is your key to unraveling the complexities of this vital statistic.

What is Fielding Independent Pitching (FIP)?

Fielding Independent Pitching in Baseball

Fielding Independent Pitching (FIP) is an advanced pitching statistic that aims to measure a pitcher’s performance independent of the fielding defense behind them.

Unlike ERA, which is highly dependent on the quality of the defense, FIP focuses only on things the pitcher directly controls – strikeouts, walks, hit by pitches, and home runs allowed. It excludes balls put into play, which are significantly influenced by the defense.

FIP calculates the number of runs a pitcher would have allowed if they pitched with league-average defense behind them. It helps isolate the pitcher’s contribution and skill, removing the noise of fielding variability. A lower FIP suggests the pitcher performed better independent of defensive support.

The logic is that since the pitcher has little control over batted balls put into play, those should be excluded from his performance evaluation. FIP aims to measure only the outcomes pitchers can directly control with their skills. This gives a more accurate picture of talent and ability.

By removing defense and luck from the equation, FIP provides a fielding-independent metric to assess pitchers on strikeouts, walks, hit batters and home runs allowed per inning pitched. This isolates the pitcher’s contribution, making it useful for analysis.

How is FIP Calculated?

The FIP formula was first created by baseball sabermetrician Tom Tango in the early 2000s to measure a pitcher’s performance independent of the team’s defense behind him.

The formula is:

FIP = Constant * (HR*13 + (BB + HBP - IBB) * 3 - K*2) / IP


  • HR = Home Runs Allowed
  • BB = Walks Allowed
  • HBP = Hit Batters
  • IBB = Intentional Walks
  • K = Strikeouts
  • IP = Innings Pitched

The FIP formula only considers outcomes that do not involve fielders – strikeouts, walks, hit batters, and home runs allowed. This allows it to isolate a pitcher’s performance from the defense behind him.

The FIP constant brings the scale of FIP onto the same scale as league ERA, and is generally around 3.2. For 2022, the FIP constant was 3.07.

The components are weighted such that home runs hurt pitchers the most, followed by walks/hit batters, then helped by strikeouts. This aligns with independent analysis showing home runs and walks have the highest correlation to scoring runs.

Why Use FIP Over ERA?

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Unlike ERA, Fielding Independent Pitching (FIP) only considers outcomes that do not involve fielders, making it independent of team defense and better for evaluating pitchers. FIP eliminates factors like errors and balls in play that a pitcher cannot directly control, instead focusing only on strikeouts, walks, hit by pitches, and home runs allowed. This makes FIP a better metric than ERA for understanding a pitcher’s true performance and skill.

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Because FIP isolates a pitcher’s performance from their fielders, it is more predictive of future ERA than current ERA. Numerous studies have found strong correlations between a pitcher’s FIP in one season and their ERA the following season. FIP helps indicate when a pitcher’s ERA is likely to rise or fall based on their fielding-independent stats. While ERA evaluates results, FIP better evaluates talent. For these reasons, many analysts rely on FIP over ERA when evaluating pitchers.

FIP’s Correlation to ERA

FIP tends to have a fairly strong correlation with ERA, though the two metrics don’t always align perfectly. Over a full season, FIP has been shown to be better than ERA at predicting a pitcher’s performance in future seasons. This is likely because FIP focuses solely on outcomes a pitcher can directly control (strikeouts, walks, home runs) rather than including defensive play and luck.

However, there can still be significant gaps between a pitcher’s FIP and ERA in a given season. This is because FIP entirely ignores balls in play, which can be influenced by a pitcher’s ability to induce weak contact. So a pitcher with a low ERA but high FIP may excel at generating soft ground balls and pop ups. Conversely, a high ERA and low FIP may indicate bad luck on balls in play. So while FIP tends to correlate well to future ERA, it does not account for all pitching skills.

Pitchers With Low FIPs

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Pitchers who consistently post low Fielding Independent Pitching (FIP) numbers generally have strong underlying performances, as FIP helps isolate their contribution from fielding and other factors.

Some standout MLB pitchers with a history of low FIPs include:

  • Clayton Kershaw (Los Angeles Dodgers) – Regarded as one of the best pitchers of his generation, Kershaw has maintained a career FIP of 2.72. He posted a remarkable 1.94 FIP in 202 innings in 2020.

  • Justin Verlander (Houston Astros) – A dominant starter, Verlander recorded a 2.65 FIP in 2022 at age 39, along with an 18-4 record and 1.75 ERA. His career FIP is 3.33.

  • Max Scherzer (New York Mets) – Scherzer has posted a sub-3.00 FIP for nine straight seasons, including a major league-best 2.29 in 2021. He averages 10.6 strikeouts per nine innings pitched.

  • Zack Greinke (Kansas City Royals) – With four top-5 Cy Young finishes, Greinke has maintained a 3.42 career FIP across nearly 3,000 innings. He recorded a 2.68 FIP in 2022 at age 38.

Having a prolonged history of keeping FIP low indicates these pitchers limit hard contact, walks, and homers – the key inputs into the FIP calculation. Their consistency speaks to true pitching talent.

Pitchers With High FIPs

Pitchers with consistently high FIPs could be an indicator that they are getting lucky or have bad defense behind them. FIP measures what a pitcher’s ERA should have been if defense was excluded, so a high FIP suggests they may actually be pitching worse than their ERA shows.

Some examples of pitchers that have posted high FIPs in recent years include Jose Urena, who had a 5.70 FIP in 2021 despite a 3.55 ERA. Tyler Chatwood had a 5.30 FIP in 47 games for the Blue Jays in 2021 while maintaining a respectable 4.30 ERA. Former All-Star Shelby Miller finished the 2015 season with a 5.11 FIP and a still solid 3.02 ERA.

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High FIP pitchers like these could see their ERAs balloon in the future if their underlying performance measured by FIP doesn’t improve. Their high FIP suggests they have been able to outperform expected ERAs thanks to factors out of their control. Whether through luck normalizing or defenders regressing, pitchers with consistently high FIPs may see ERAs rise to match their FIPs over time.

FIP’s Applications

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FIP has several key uses in baseball analysis and evaluation.

One of the main applications of FIP is predicting future performance. Since FIP focuses solely on outcomes pitchers can control like walks, strikeouts, and home runs allowed, it can give a good indication of how a pitcher may perform going forward, independent of factors like defense and luck. FIP has been shown to be more predictive of future ERA than ERA itself.

Another important use of FIP is evaluating pitchers independently of the quality of their defense. Since batted balls in play involve fielders to convert them into outs, ERA is partially dependent on defensive skills. FIP removes this factor and isolates just the pitcher’s contribution. This allows for more accurate comparisons of pitchers across teams and eras.

FIP is also useful for comparing pitchers across different eras in baseball history. As offensive levels have varied over decades, ERAs from different periods can’t necessarily be directly compared. However, FIP provides a metric tied solely to pitching that adjusts for context and allows analysts to evaluate pitchers from any era on a level playing field.

FIP’s Limitations

While FIP is useful for evaluating pitchers, it does have some limitations.

First, FIP does not account for every factor that goes into pitching. It focuses solely on strikeouts, walks, hit batters, and home runs allowed. However, it does not consider batted ball types, defensive play behind the pitcher, pitching from the stretch vs. the windup, and some other factors that influence run prevention.

Additionally, although FIP aims to isolate pitching from fielding and luck, it is still somewhat correlated with ERA. Pitchers with very low or very high ERAs tend to have correspondingly low or high FIPs. So while FIP does a good job estimating a pitcher’s true talent level, ERA and its factors still creep into the metric to some degree.

Finally, while FIP is a useful stat, it is not the only advanced metric available. Stats like xFIP, SIERA, DRA, and others also aim to evaluate pitching performance by isolating it from defense and luck. Each metric has its own strengths and weaknesses. Looking at a combination of stats can provide a more complete picture of a pitcher’s abilities.

So in summary, FIP has limits in accounting for every pitching factor, eliminating ERA correlations, and standing alone as the best metric. Using FIP along with other advanced metrics provides a more comprehensive analysis.

Notable Seasons Analyzed by FIP

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FIP can reveal insights into pitcher performance that traditional stats like ERA may obscure.

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Here are some notable seasons where FIP analysis told a different story than ERA:

  • In 2015, Cubs starter Jake Arrieta had an excellent 1.77 ERA and won the Cy Young award. However, his 2.35 FIP was still good but not as spectacular, indicating he may have benefited from some luck. The next season, his ERA regressed to a more expected 3.10 as his FIP rose slightly to 2.52.

  • Dodgers starter Hyun-Jin Ryu had an amazing 2.32 ERA in 2019 but his 3.10 FIP was more pedestrian. The next season, his ERA ballooned to 4.98 while his FIP remained steady at 3.19. This shows how FIP more accurately assessed Ryu’s true pitching talent.

  • In 2017, Orioles closer Zach Britton posted a 2.89 ERA but his excellent 1.94 FIP demonstrated his dominance. He was able to limit hits on balls in play, so his ERA underrated his performance.

By comparing FIP to ERA, analysts can better judge whether an exceptional or poor season was earned or influenced by chance. This helps identify over and underperformers.

The Future of FIP

FIP will likely continue to be used alongside ERA and other pitching metrics to evaluate performance. While ERA measures real results, FIP aims to isolate a pitcher’s performance from external factors like defense and luck. Comparing the two helps identify cases where a pitcher’s ERA may be higher or lower than their “true” skill level.

As sabermetrics and data analysis advance, refinements to the FIP formula will likely be proposed and tested. For example, fly ball tendencies and power of hitters faced could be incorporated. However, major changes may only come if the correlation between FIP and ERA diverges over time. As long as FIP continues predicting future ERA well, the core formula will likely remain similar.

FIP provides a fielding-independent evaluation to complement ERA. While not a perfect metric, FIP’s simplicity and predictive power ensure it will continue serving a role in baseball analysis. Refinements may come, but the principles of isolating pitching from fielding and luck will remain FIP’s foundation.


Is a lower FIP always better?

A: Yes, a lower FIP is generally considered better, as it indicates a pitcher’s ability to prevent runs independent of team defense. However, it’s crucial to consider other contextual factors.

How does FIP differ from xFIP?

A: xFIP (Expected Fielding Independent Pitching) adjusts FIP by normalizing home run rates. It replaces a pitcher’s actual home run rate with a league-average rate, providing a more stable metric.

Can FIP be used for relievers and starters alike?

A: Yes, FIP is applicable to both starters and relievers. It offers a standardized measure to assess pitching performance across various roles.


In the realm of baseball analytics, FIP stands as a powerful tool for unraveling the intricacies of a pitcher’s true performance. As we decode the formula and understand its significance, FIP emerges as a crucial metric that paints a clearer picture of a pitcher’s abilities.

So, the next time you delve into the stats of your favorite pitcher, remember the influence of FIP in revealing the true mastery of the art of pitching in the world of baseball.

Adrian Cook
Adrian Cook

Hello, I'm Adrian Cook, and I am the author of BaseballMatchDay.com. I have a deep-rooted connection to baseball as I was once an avid player of the sport. Baseball has always held a special place in my heart, and my personal experiences as a player have shaped my understanding and love for the game. Having been on the field, I intimately understand the intricacies, challenges, and joys that come with playing baseball. It is this firsthand experience that allows me to bring a unique perspective to the content I create.

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