After a quality college career that saw Auburn’s Tank Bigsby average nearly 1000 rushing yards per season in the premier conference in the country, the word that best encapsulates my feelings toward Bigsby’s capabilities as a runner is “frustrating.”

As a freshman in 2020, Bigsby ran all over the SEC, putting together three straight 100-yard rushing performances against conference opponents starting in the third game of his career, and he capped off the year with a 192-yard showing against Mississippi State in the Tigers’ regular season finale. Bigsby legitimized those box score numbers with high-level efficiency:

As a true freshman at a powerhouse program, Bigsby averaged 1.48 yards per carry greater than other Auburn backs, a group that earned a collective 3.68-star rating as high school recruits, making them an 89th-percentile cohort. More impressively, the 19-year old Bigsby did all that while seeing heavier defensive fronts than did his teammates and while shouldering a legitimate workload (he averaged just under 14 carries per game).

Given the box counts that he saw relative to those his backfield mates carried the ball against, the average Bigsby rushing attempt produced nearly 150% the output of the average carry by all non-Bigsby running backs at Auburn in 2020, a Box-Adjusted Efficiency Rating that is exceeded by just four lead backs in the SEC in the last five years (all of whom posted their numbers as upperclassmen).

Bigsby was also an incredibly consistent runner that season, creating positive outcomes on his attempts 11.5% more often than other Tiger backs were, good for a Relative Success Rate bested by just two lead SEC backs going back to 2018 (both of whom, including 2022 draftee Dameon Pierce, were upperclassmen).

Put simply, Bigsby was one of the best freshman running backs in SEC history, and you could make a decent argument – given his age and the pedigree of the other players in the backfield at the time – that freshman Bigsby put together the most impressive single season of any running back in college football in the last half-decade (as far back as these box count-centric metrics go). If we were evaluating Bigsby based solely on what he did that year, he’d be right up there with Bijan Robinson and Jahmyr Gibbs as one of the premier backs in this class.

Many evaluators will likely maintain that Bigsby belongs there even still, but the case for him as a top guy in what is looking like a stacked crop of 2023 runners might be a bridge too far after the struggles he experienced in both 2021 and 2022:

Bigsby’s massive drop-off in per-carry efficiency came as quite a surprise in 2021, and considering the incredible season he had the year prior, it seemed reasonable to give him the benefit of the doubt going into his junior campaign. Amazing players don’t suddenly become bad players, and it was speculated that Bigsby was toughing out some undisclosed injury during that sophomore season.

The problem is that his 2022 performance kind of split the difference (though perhaps I’m being too kind), and we’re left with a player who, relative to all FBS-level runners, was incredible as a freshman, terrible as a sophomore, and pedestrian as a junior. On aggregate, Bigsby’s perplexing career produced the following final numbers (with percentile ranks now relative to eventual NFL backs):

For further reference, these marks are nearly identical to those posted by Kyren Williams, who was selected by the Rams in the 5th round of last year’s NFL Draft (Williams ended his Notre Dame career with a BAE Rating of 106.4% and an RSR of 0.5% while playing with backfield teammates who averaged a 3.04-star rating as high school recruits, while Bigsby’s teammates earned a collective 3.05).

Using these career numbers, Bigsby earns a 37.2 (out of 100) in a composite rushing efficiency score that I generate to encapsulate the quality of a player’s contributions on the ground. That number would slot Bigsby right between Snoop Conner and Greg Bell in the bottom half of last year’s running back class. While not quite Isaiah Spiller levels of bad, as another three-year producer out of the SEC with underlying efficiency metrics that don’t substantiate Day 2 hype, Bigsby certainly has shades of Spiller in his profile.

In a more focused sense, I also like to generate comparisons between players using this hard data, revealing the historical prospects whose profiles most resembled that of a current prospect in a particular category. One of those categories is the “pure runner” comp, which compares players based only on their rushing efficiency metrics and their physical profiles. If we assume that Bigsby measures in at 5’11 (and 3/8”) and 217 pounds (which is what I project based on historical weight gain patterns for eventual NFL runners in addition to Bigsby’s own historical listed heights/weights), has a 35” vertical, and runs 4.50 in the forty-yard dash at the Combine, the following ten backs score as the most similar to him from that perspective:

Obviously, there are some exciting names here in guys like JK Dobbins and Breece Hall, but the common thread running through this list is good athletes from Power 5 programs who, despite big play ability, largely failed to produce efficiently relative to their college teammates. Here are the career YPC+ and Breakaway Conversion Rate marks for each of those players:

Personally, my main takeaway here is that Bigsby probably belongs to a sub-category of running backs who thrive in college based mostly on physical and/or athletic advantages. He’s always posted solid numbers in the open field, and he’s also been a good tackle-breaker for most of his career (save for during his allegedly injury-riddled 2021 campaign).

According to Pro Football Focus’ missed tackles forced metric, Bigsby broke away from defenders at an elite rate in both 2020 and 2022, as his 0.34 missed tackles forced per attempt mark in each of those seasons would be the second-highest career mark among all running backs drafted since the metric was first tracked back in 2014 (behind only Javonte Williams and just ahead of Kenneth Walker and David Montgomery. His actual career mark, which does include his down sophomore season, is a 0.29 that still lands in the 88th-percentile.

The physical gifts that show up on film for Bigsby are also clear in the metrics, but the fact that those things haven’t always resulted in efficient output on a per-carry basis makes him a bit of an enigma. The more-athlete-than-runner category that he seems to fit into isn’t necessarily a bad one, but it is true that the large-scale track record for those types of backs living up to their potential isn’t great. Proceed with caution.