2022 Bears Backfield Breakdown: David and Khaliath

by Noah Hills · Analytics & Advanced Metrics

The 2022 Bears Backfield Breakdown is part of an offseason series in which I take a deep dive into one NFL team’s backfield and examine the respective rushing performances of the players in it. In doing so, I hope to gain insights into key players from a talent evaluation standpoint, and using that evaluation as a baseline, from a dynasty valuation standpoint. The first installments in the series can be found here.

I’ll start by taking a quick overview of each team’s raw rushing volume and propensity to run the ball in general, and then dive into the player evaluation portion. Before we start, let’s define the metrics I’ll use as part of those evaluations:

Key Metrics

Yards per Carry+ (or YPC+)

The degree to which a player’s raw yard per carry average exceeds or falls short of the collective yard per carry average of all other running backs on his team. Meant to be an overview of a player’s team-relative efficiency.

Box Count+

The degree to which the average amount of defenders in the box that a player faces on his runs exceeds or falls short of the collective average faced by the other running backs on his team. Considering that the outcome of any given rushing attempt is largely dependent on the amount of defenders in the box pre-snap, Box Count+ describes the relative degree of difficulty of a running back’s carries.

Breakaway Conversion Rate (BCR)

Quantifies performance in the open field by measuring how often a player turns his chunk runs of at least 10 yards into breakaway gains of at least 20 yards.

Box-Adjusted Efficiency Rating (BAE Rating)

Improves upon YPC+ by accounting for the box counts that a player carried the ball against. Looks at team-relative yards per carry against each individual box count, then uses a weighted average (based on total carries against each box count) to generate an overall score. A score of 100-percent indicates that a player is producing exactly the per carry output of his teammates, a score above 100-percent indicates that he is outdoing their per carry output to whatever degree, and vice versa for a score below 100-percent.

Relative Success Rate (RSR)

Measures player consistency using Success Rate, but relative to his teammates and adjusted for the box counts that he faced in the same way that BAE Rating is. “Success” on a given carry is defined by gaining 40-percent of yards needed on first down, 70-percent of yards needed on second down, and 100-percent of yards needed on third or fourth down. A score of 0.0-percent indicates that a player is succeeding on exactly the same percentage of his carries as are the other backs on his team, a positive score indicates that he is succeeding more often than his teammates are, and vice versa for a negative score.

Composite Efficiency Score (CES)

Presents a single-metric overview of the quality of team-relative performance a player produced on his carries in a single season. Calculated using the average of a player’s percentile ranks in Box-Adjusted Efficiency Rating and Relative Success Rate, represents player performance on a 0-100 scale.


Team Rushing Volume

The Chicago Bears ran the ball 475 times in 2021, finishing No. 11 in the league in total rushing attempts. Last season marks only the second time in the Matt Nagy era that Chicago was in the upper half of the NFL in rushing. They finished No. 27, No. 21, No. 6, and No. 18 in his other four years with the team.

In early-down and neutral Game Script situations (when win probability for either team did not exceed 80-percent), the Bears were the seventh run-heaviest team in the league last season (according to rbsdm.com), showing a commitment to running the ball even though they weren’t a very strong team overall. They also ran the ball more often than expected (given league-wide play-by-play data) in most down-and-distance situations, and two-percent more often than expected overall.

Nagy is now out, and replacing him is the defensive-minded Matt Eberflus along with new offensive coordinator Luke Getsy. This will be Getsy’s first stint leading an NFL offense. But he was on Matt LaFleur’s offensive staff in Green Bay for the past three years. During that time, the Packers were No. 26 in the league in early-down run rate. Having a young Justin Fields at quarterback is a bit different than having an MVP-caliber Aaron Rodgers. And it remains to be seen how Getsy’s tendencies and overall philosophy differ from LaFleur’s.

Efficiency Numbers

David Montgomery was a high-volume lead runner for the third year in a row in 2021. He finished with the ninth-most carries in the league. Khalil Herbert was the main man behind him. Followed by spot duty from Damien Williams and a solitary rushing attempt from Ryan Nall. Here are the complete rushing efficiency profiles for each of those four backs:

For the first time in his career, Montgomery was a net-negative in the running game last season. After producing Composite Efficiency Scores of 67.4 and 56.7, respectively, in his first two years, his performance dipped to the 29.2 level in 2021. Based on that composite, he was the worst starting running back in the league and the only one with a score below 30.0.

On the other hand, Herbert was one of the best backup runners in the NFL. He was more efficient overall and more consistent on a per-touch basis than Montgomery and the other Bears runners collectively. His 71.3 CES ranked No. 3 among guys who had at least 100 attempts as their team’s second-leading ballcarrier.

Williams was also solid in a small role. Though he didn’t offer much dynamism on his carries, he consistently produced positive outcomes. Evidenced by an 88th-percentile Relative Success Rate.

So Now What?

David Montgomery will be 25 by the time the season starts. It’s worth wondering how much more he has to give. He’s not a guy who relies on upper-tier athleticism in order to be effective. But he’s now posted two straight seasons with RSR marks below the 40th-percentile. We often see these slower-footed backs provide value through churning out consistent yardage and avoiding negative plays even in the absence of open-field dynamism. Montgomery hasn’t done that since he was a rookie.

Khalil Herbert‘s long-term value is subdued by the fact that he himself will already be 24 during the 2022 season. I also think the Bears are more likely to transition from Montgomery to another mid-high draft capital investment at running back in the next year or so rather than just hand the keys of the backfield over to Herbert in any meaningful way. For the time being, though, he is being appropriately valued as one of the best handcuffs in dynasty.

Damien Williams is now in Atlanta, being replaced in the Bears backfield by Darrynton Evans. An overrated prospect as an undersized guy who doesn’t offer great value in the passing game, Evans has been cursed by injuries through two seasons in the league. He’s a Travis Homer-type role player at best.

Final Word

I’m not a huge fan of any Bears running backs at their current costs in dynasty. Khalil Herbert is a fine value. But as with most backs in the RB20-30 range, I’m likely opting for wide receiver over David Montgomery in startups. If I can move him to acquire Rashaad Penny plus pieces in a trade package, I’m doing it all day.