Analyzing Offensive Line’s Effect on Running Back Performance (Fantasy Football)

Introduction

In fantasy football, the performance of running backs is often scrutinized for insights that can lead to winning picks. One crucial, yet sometimes overlooked factor, is the impact of offensive lines on these players. A strong offensive line can create substantial running lanes and provide better protection, directly enhancing a running back’s ability to gain yards and score touchdowns. In contrast, a poor offensive line may allow their back to be tackled before they even reach the line of scrimmage. This article will explore whether the strength and effectiveness of offensive lines significantly influences the fantasy value of running backs.

Approach

To investigate the extent of an O-line’s impact on running backs, I first needed a way to ‘grade’ O-lines. To do this, I gathered a number of important offensive line metrics for each team, which included average time to throw (weighted by number of rushers), pressure percent, average expected rush yards, average time to line of scrimmage (run plays), average yards until contact (run plays), and expected fantasy rush points per game. Following this, I put together a simple multi-linear regression model to see which metrics were the most important in predicting fantasy rush points per game. The results showed average time to throw, pressure percent, and average expected rush yards were the most influential. With this, I comprised an overall offensive line rating using a weighted summation of the z-scores for each metric. Finally, I scaled the ratings between 0 and 1 to make them more comprehensive and interpretable.

Analysis

After creating ratings, I plotted each team’s rating against their expected rushing fantasy points per game. The results were fantastic. We see a fairly strong relationship between the two variables, especially towards the tails of the graph. The R-squared value is 0.43, telling us that 43% of the variance in the Y variable can be explained by variance in the X variable. It may not seem like it, but this is fairly high for real-world problems like this. Notice most of the randomness comes from teams whose ratings fall somewhere in the middle.

Next, we need to look at the actual performance of running backs in comparison to offensive line play to see if this relation holds. If the graphic looks much different, we’ll have a problem. Here, the y-axis shows the difference between the actual average rushing fantasy points per game and the expected average rushing fantasy points per game.

Fortunately, the results are great! We see a graph that looks very similar where the tails of the range tend to be more predictable with running back performance. The R-squared value is a bit lower, falling at 0.34. This tells us that true running back performance is more random than expected running back performance. That is, running back talent plays a big role in fantasy success.

The question is, how big is that role? Let’s break it down.

91.67% of teams with an O-line rating of 0.5 or higher (better than average) average more expected fantasy rush points than average (17.1 points). Only 25% of the teams with rating lower than 0.5 meet this threshold. This tells us that a good offensive line is crucial in providing the opportunity for RBs to succeed. With a good line, there is a near guarantee that the back behind them will have ample opportunity to produce.

50% of teams with a rating over 0.5 have efficient RBs (those who score more fantasy points than expected). Only 8.3% of teams with a rating under 0.5 have efficient RBs. This tells us that running backs typically do not succeed with poor offensive lines. It is also important to note that even with a good line, there is a chance a running back underperforms — this goes to show that RB skill is key in fantasy as well.

Below, you can find the offensive line ratings from the 2023 season, along with the expected and actual total fantasy points per game numbers.

Conclusion

Offensive lines play a large role in running back performance. While we saw that RB talent is important (only 50% of backs with good lines succeed), it is extremely difficult for them to efficiently produce without a secure front. Moving forward, before you judge a running back, determine if their offensive line is adequate first. While backs with poor lines can still succeed, it would be smart to primarily target those with strong ones.