The 2022 Chiefs 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. Then, I’ll dive into the player evaluation portion. Before we start, let’s define the metrics I’ll use as part of those evaluations:
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.
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 number 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.
Measures the disparity between a running back’s percentile ranks in BAE Rating and RSR in order to indicate how volatile a player’s per-carry performance is. High overall efficiency paired with low rate of success indicates boom/bust output, while low overall efficiency paired with high rate of success indicates steady, low-ceiling output. Measures degree of volatility, not quality of performance.
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 Kansas City Chiefs were one of the lowest volume rushing teams in the league in 2021. Their 431 carries ranked No. 20 in the NFL and were 22 fewer than league average. They’ve been similarly (and even more) pass-happy in the previous three years of the Patrick Mahomes-Andy Reid partnership. The Chiefs finished No. 23, No. 27, and No. 23, respectively, from 2018 to 2020.
According to rbsdm.com, the Chiefs have been one of the least run-centric offenses in the league in the last few years. This is not just in total volume but also in terms of situational play-calling. On early downs in neutral game script situations (when win probability for either team did not exceed 80-percent), Kansas City ran the ball more often than only the Buffalo Bills last season. From 2018 to 2020, they were far and away the lowest-ranked team in that category. During this time period, the Chiefs ran the ball only 35.9-percent of the time. The second-lowest, Pittsburgh, ran the ball 41.3-percent of the time from 2018 to 2020.
The Chiefs also ran the ball infrequently considering the down-and-distance situations last year. Using league-wide play-by-play data to guide play-calling expectations, rbsdm.com found that the Chiefs opted to throw more often than expected in virtually every situation in 2021, including 10-percent more often than expected overall.
Not much has changed with the relevant personnel in Kansas City going into 2022. Mahomes is back, Reid is back, and offensive coordinator Eric Bieniemy is back. Tyreek Hill is obviously now in Miami. However, the Chiefs did their best to reload at wide receiver. We should assume their intention is to be one of the NFL’s best and highest volume passing offenses once again. This will likely mean another below-average year for their rushing volume.
Darrel Williams was the surprise carry leader in the Chiefs backfield in 2021. He won the war of attrition as Clyde Edwards-Helaire finished No. 2 on the team while playing in only 10 games. Behind them, Derrick Gore saw regular work while Jerick McKinnon handled spot duty before coming on strong in the playoffs. Here are the complete rushing efficiency profiles for each of those four runners:
Williams saw playing time in Kansas City because he doesn’t fuck things up. He consistently gets what is blocked, and he excels in pass protection. The is evidenced by his stellar Relative Success Rate. Williams’ performance there was in the 85th-percentile in 2021, following up a 65th-percentile showing on 41 carries in 2020. Outside of that, however, he doesn’t have much dynamic juice. His -60.7 Volatility Rating indicates per-carry output that is on the extreme end of low-ceiling, high-consistency output. This is the second lowest among all running backs with at least 100 carries in a season since 2016, with only 2021 Jamaal Williams lower.
Edwards-Helaire failed to produce a positive RSR. However, his Box-Adjusted Efficiency Rating was above the 100-percent mark for the second year in a row. He did a better job of producing positive outcomes consistently as a rookie with a 61st-percentile RSR of 1.8-percent. Edwards-Helaire also excelled in that area in college. Edwards-Helaire posted a 5.8-percent RSR on 146 carries at LSU in 2018. He followed it up with a 5.9-percent mark on 214 attempts as the lead back in 2019. Edwards-Helaire was also more efficient than the other backs at LSU, with BAE Ratings in the 55th and 94th- percentiles, respectively, in 2018 and 2019. Last season was the first time in five years that we’ve seen Edwards-Helaire lag behind his teammates in even one of those key efficiency metrics.
The Best of the Rest
Nearly the opposite of Williams, Gore offered efficient-yet-boom/bust output on his carries. He’s bounced around training camps and practice squads since entering the league as a UDFA in 2019. It’s nice to see a guy like that make the most of his opportunities.
McKinnon was a key part of the Kansas City offense during the playoff run. However, his regular season workload wasn’t very conducive to strong evaluation. Nonetheless, he was both efficient and consistently successful on his 12 rushes.
This backfield looks very different going into 2022 than it did last season. Williams is now an Arizona Cardinal. McKinnon is currently a free agent. The team added Ronald Jones, seventh-round rookie Isiah Pacheco, and UDFA Tayon Fleet-Davis.
Jones has posted a positive RSR in every season of his career. While his BAE Rating dipped to a 39th-percentile mark of 93.3-percent last season, he performed at levels in the 82nd and 94th percentiles, respectively, in that area in the previous two years. He’s a quality two-down runner who I’m legitimately excited about seeing in this offense.
Pacheco is a 5-10, 222-pounder with 4.37 speed. Despite playing on abysmal offenses at Rutgers, he posted BAE Ratings above the 75th-percentile in every season but his last. In that season, he dipped just below the 50th percentile with a mark of 99.5-percent. He was a volatile runner in college, however, producing negative RSRs in three of his four seasons. There’s a chance that he was trying to make something out of nothing behind a sieve offensive line. He also could be a raw athlete who lacks some nuance as a pure runner. I don’t think he offers much as a pass-catcher. Nonetheless, Pacheco is an interesting player who I’m coming around on after probably being too dismissive of him earlier this offseason.
Fleet-Davis was not on my radar pre-Draft, but he was very efficient (though also very volatile) as Maryland’s lead back as a fifth-year senior in 2021. He also caught 32 passes while listed at 220 pounds last year, so the ingredients are here for an intriguing profile.
The Chiefs have a great offense, and the most expensive player in this backfield is Edwards-Helaire who is currently being drafted as the RB28 in dynasty. He’s been left for dead after two disappointing seasons, but he’s shown enough as a runner that I’m not hopping off the bandwagon yet. If he can reach his potential as a receiver (which probably means learning to pass-block), the CEH dream might not be over yet.
The other guys are also all interesting at cost. Jones is a good runner who could secure the early-down and goal line work on one of the best offenses in the league and is currently being taken as the RB49. Pacheco is a size/speed specimen with upside, is being drafted as the RB71 in startups, and can be had in the fourth round of rookie drafts. Fleet-Davis is completely free.
It’s very possible that this backfield ends up being a mess. It may turn out fantasy gamers won’t want to start any of these guys on a weekly basis. However, it doesn’t cost much to find out if we’re wrong, and there’s reason to be at least a little bit optimistic about all of these dudes.