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LOB Baseball: Unpacking The Left On Base Statistic

Written by Chris 

Published on February 22, 2024

In baseball, every statistic counts. Whether it's home runs, batting average, or left on base (LOB), each number contributes to a team's success or failure. In this article, we will address the question "What does LOB mean in baseball" and why is the LOB baseball stat an important one to track? We will also explore its significance in determining a team's offensive performance, and how teams can improve their LOB percentages to increase their chances of winning.

What Does LOB Mean In Baseball?

Left on Base or LOB for short is a baseball stat that measures the number of baserunners who do not score a run and remain on base at the end of an inning. LOB is calculated by subtracting the number of runs a team scores in an inning from the total number of baserunners who reach base safely in that inning. For instance, if a team has six baserunners reach base in an inning but only three score, they will have three runners left on base.


The LOB statistic is big in baseball because it shows a team's ability to score runs. A high number of LOB indicates that a team is not making the most of its scoring opportunities. This can result in fewer runs scored and fewer wins. On the other hand, a low LOB number indicates that a team is good at converting their opportunities into runs.

LOB can also be compared to other batting statistics, such as batting average and on-base percentage. This would help provide a more complete picture of a team's offensive performance. A team that has a high batting average but a high LOB may not be as effective as a team with a lower batting average but a lower LOB.

Evaluating Hitters Using The LOB Baseball Stat

LOB is particularly important when assessing a hitter's situational hitting skills. A hitter who consistently leaves runners on base may not be making the most of their at-bats. If a hitter fails to drive in runners in scoring position, their LOB percentage will be high. This would indicate that they are not performing well in crucial situations.


A hitter's LOB can also be used to compare their performance to other players on their team or in the league. For instance, a team that consistently leaves runners on base may need to focus on improving their situational hitting or finding ways to get runners home.

Why Is LOB A Flawed Stat For Evaluating Hitters?

While left on base (LOB) is a crucial stat for evaluating a hitter's situational hitting skills, it's important to note that using LOB percentages as the sole measure of a hitter's performance can be flawed.


Firstly, LOB does not account for a hitter's performance when there are no runners on base. For instance, a hitter with a high LOB percentage may not be getting as many opportunities to drive in runs if their team is struggling to get runners on base.


Secondly, LOB does not account for factors beyond a hitter's control, such as baserunning or the opposing team's defensive play. A hitter may hit a ball hard with runners in scoring position, but if the other team's defense makes a crazy play, the hitter's LOB percentage will still increase, despite their solid hit. A runner can also be tagged out or called out as part of a double play or fielder's choice. Those runners would still be considered left on base. The LOB stat does not factor in quality at bats (QABs).


Thirdly, a hitter could advance a runner to scoring position via a bunt or sac fly and their LOB percentage could be negatively impacted. However, they are essentially setting the table for the next hitter to drive them in. It's a team game and strategy plays a huge role.


Lastly, LOB percentages may not always reflect a hitter's overall value to their team. For example, a leadoff hitter's primary goal is to get on base, not necessarily to drive in runs. Therefore, they may have a high LOB percentage but still be valuable to their team if they consistently get on base and set the table for the middle of the lineup.

Our Favorite LOB Baseball Flaw

My favorite situation showing just how flawed the LOB stat is is with the home team up in their last at-bat. Let's say that the bases are loaded and the game is tied. The hitter singles up the middle to score the runner from third. Even though the game ends in walk-off fashion, those runners left on first, second, and third base would be negatively factored into the LOB percentage.

Evaluating Pitchers: Role of The LOB Baseball Stat

If you flip it around, LOB can also be an important stat when evaluating pitchers and their performances.


Evaluating a pitcher's performance goes beyond just looking at their win-loss record or earned run average (ERA). The LOB baseball stat helps assess a pitcher's ability to control the game's pace and limit scoring opportunities for the opposing team.


LOB reflects the number of runners that a pitcher strands on base and doesn't allow to score. Therefore, pitchers with a high LOB percentage are considered to be more effective in crucial situations, such as with runners in scoring positions.


For example, if a pitcher allows five baserunners in an inning but manages to get three outs without giving up any runs, they will have a LOB percentage of 60%. On the other hand, if the same pitcher allows five baserunners and gives up four runs, their LOB percentage drops to 20%.


LOB can be especially useful in evaluating relief pitchers, who often enter the game with runners on base. A high LOB percentage for a relief pitcher indicates that they are effective in preventing inherited runners from scoring and can be trusted to close out close games.


High strikeout pitchers have more control over their LOB% than those who rely on their team's defense. They are able to pitch their way out of difficult situations and maintain a LOB% higher than the league average of 70-72%, which can result in a lower ERA. However, most pitchers tend to have LOB percentages that are similar to the league average.

Since 1901, the highest single-season LOB% by a starting pitcher was 94.4% by Babe Adams in 1920. (Source: Baseball-Reference)

Improving LOB Statistics

Reducing the number of runners left on base is a critical component of winning baseball games. To improve their LOB statistics, teams need to focus on situational hitting and executing in critical moments. This means that players need to be able to hit with runners in scoring position, make contact when necessary, and take advantage of their opportunities. By reducing their LOB, teams can increase their chances of scoring more runs and ultimately winning more games.

LOB In Baseball - MLB Leaders

Ryan Zimmerman

14 runners LOB

5-8-2016

AL - 13 Innings

Dustin Pedroia

13 runners LOB

9-15-17
AL - 15 Innings

Most Runners Left On Base In A 9 Inning Game

NY Yankees with 20 runners LOB
9-21-1956

Final Thoughts

In conclusion, the left on base (LOB) statistic is an important measure in evaluating both pitchers and hitters in baseball. While it may not be the end-all, be-all for determining a player's worth, it provides valuable insight into a player's ability to handle pressure situations and limit damage on the field. As we've seen, a high LOB% can often indicate a pitcher's skill at working out of tough spots, while a low LOB% may suggest a need for improvement. But don't worry, even the greatest pitchers and hitters have off days and can't strand and drive in every runner.