by Scott Spratt
The 300-carry running back may be on his last legs, but specialized running backs are becoming increasingly popular as offenses look to create mismatches with players with positional flexibility. That makes it more important than ever to distinguish between personnel and formations. Bryan Knowles reviewed the former for 2018 a few weeks ago. This article will detail teams' frequency of and success on carries with one and two backs in their backfields.
The two are certainly related. The marked increase in 11 personnel—one running back and one tight end—across the league has mirrored the decline of runs from two-back formations. But different formations provoke different defensive responses, and that tug-of-war creates compelling winners and losers among teams that rely heavily on two-back sets and those that don't.
For the purposes of this analysis, we're considering rushing attempts by any player who was lined up in the offensive backfield but was not at the quarterback position. Single-back formations include any play where one player other than the quarterback lined up in the backfield and ran the ball; two-back or multiple-back formations include any play where more than one player other than the quarterback was in the backfield, and one of those players ran the ball. The numbers include direct snaps to a player who was lined up as a running back but do not include scrambles, quarterback keepers, wide receiver or tight end end-arounds or reverses, or "Wildcat"-style plays. They only include runs by a player lined up as a running back at the snap.
|Running with 1 or 2 RB in Formation (Not Personnel), 2018|
|1-RB Rushes||2-RB Rushes||Difference|
|Off||Pct of 2+ RB||Att||DVOA||Rk||Att||DVOA||Rk||DVOA||Rk|
The 49ers (59 percent) and Patriots (57 percent) duked it out for the lead in percentage of carries from two-back formations, well clear of the third-place Ravens (37 percent). That makes two straight years in the top spot for the 49ers, who telegraphed their reign in early 2017 with the firing of head coach Chip Kelly and signing of fullback Kyle Juszczyk to a contract with twice the guaranteed money of that of the next-richest fullback.
Kelly's lone season in San Francisco was the team's only one since 2011 outside of the top three in attempts from two-back sets. They finished 32nd that year with 11 such carries. The 49ers have had patience with a handful of unsuccessful coaches since their dynasty of the '80s and '90s, but Kelly lost in a fashion antithetical to their preferred brand of football. Kyle Shanahan encouraged carries from two-back sets as offensive coordinator in Atlanta, Cleveland, and Washington, and better fits with the team's self-image.
The 49ers' reliance on a fullback may seem old-fashioned, but it worked for them in 2018, when they ranked 14 spots better in rushing DVOA from two-back sets than with a single back. But despite that success and the history of both the team and its head coach, it will be interesting to see if they persist with the strategy in future seasons. It's easy to play a fullback when your No. 1 wide receiver is Kendrick Bourne. Now that the 49ers have reloaded with second- and third-round draft picks Dante Pettis, Deebo Samuel, and Jalen Hurd, they seem well-positioned to run plays with 11 personnel.
Compared to the 49ers, the Patriots are a relative newcomer to two-back sets. Prior to 2016, they were bottom-10 in percentage of runs with two backs in the backfield. But in each of the last three seasons, the Patriots have been among the top three teams; last year, they were more successful with the strategy than the 49ers and every other team of note. They were the effective leader with a 1.5% DVOA on those two-back rushes—the Bengals, Redskins, and Packers were all a bit better, but all on fewer than 40 such carries.
The Patriots' ramp-up of two-back sets has coincided with the development of James White, but he isn't its driving force. White spends the bulk of his snaps as either the lone back or split wide. Instead, the Patriots rely on fullback James Develin almost as much as the 49ers rely on Jusczcyk, especially when they hand the ball to their traditional ballcarriers.
Over the last three seasons, the Patriots' many backs have been remarkably similar on their attempts with Develin on the sideline. Tom Brady and his dangerous passing attack does much of that work for them, encouraging defenses to plan for the pass and react to the run. But when the team needs to run the ball, some of their backs have been better than others running behind Develin.
|YPC With and Without James Develin, Patriots RBs, 2016-18|
|Player||With%||Yards Per Carry|
Sony Michel acquitted himself well as the team's power back in 2018. His 4.4 yards per carry with Develin on the field was similar to his efficiency without Develin and buoyed the Patriots' rushing performance in two-back sets—Michel had more than twice as many carries behind Develin (137) as Rex Burkhead (39) and James White (21) combined.
Injuries have limited Burkhead to 121 carries in his two-year Patriots career, and possibly his effectiveness on those carries. But his lack of efficiency behind Develin has not fit well with his role with the team—he has taken three-fifths of his carries with Develin on the field, a nearly identical rate to that of former Patriots power back LeGarrette Blount. Burkhead may follow Blount out the door as a preseason roster cut with third-round rookie pick Damien Harris adding one body too many in their backfield. Or maybe not—Dion Lewis showed that these performance splits aren't a crystal ball to predict Bill Belichick's roster decisions, and Burkhead is also a capable pass-catcher.
The 49ers and Patriots were exceptions by both their frequency of runs from two-back sets and their success with them. For most of the past decade, teams had performed about as well from two-back sets as they had on single-back plays. You can see this in DVOA—teams have consistently averaged more yards per carry from one-back sets, but since two-back sets are used more frequently in short-yardage scenarios, they don't need as many yards to be successful. But in 2018, teams performed much better from single-back sets, enjoying a decade-high +0.7 yards-per-carry and +11.3% DVOA advantage versus two-back sets.
|League Running with 1 or 2 RB in Formation, 2011-18|
|Season||Pct of 2+ RB||1-RB Rushes||2-RB Rushes||Difference|
Like so many things in football, a fullback creates collateral damage beyond his blocking. His presence on the field announces to the defense an intention to run the ball, and defenses respond with strategies better suited to stop a run. With teams relying more and more on 11 personnel and enjoying better success with it, especially in the passing game, it is plausible that backs will continue to perform better without a fullback to block for them.
The Rams run that modern type of offense to perfection. They led all teams in 2018 with an 18.1% rushing DVOA from single-back formations and took just one carry from a two-back set all season. It is a marked change from the team's final two years in St. Louis, when they led the league in percentage of carries from two-back formations. That Sean McVay-spurred change in approach has paid major dividends, flipping the team from the bottom 10 in rushing DVOA from single-back formations in 2015 and 16 to the top 10 in the last two years. Todd Gurley was with the team all four seasons.
The Bears and Colts increased their reliance on single-back runs by 19 and 18 percent, the most and second-most in football in 2018. As with the Rams the year prior, those strategic shifts followed coaching changes. Matt Nagy and Frank Reich each have ties to Andy Reid, the former as Reid's offensive coordinator in Kansas City, and the latter as coordinator in Philadelphia for Doug Pederson, who himself coached under Reid for the Chiefs before Nagy did. The Bears, Colts, Eagles, and Chiefs combined for just 113 attempts from two-back formations last season, and they all performed better with their ballcarriers alone in the backfield.
The Packers and Bengals weren't far behind with 17 and 16 percent increases in their respective percentages of single-back runs. It's a little less clear if those trends will continue in 2019 since both teams will have new coaches, but Zac Taylor and Matt LaFleur each come from Sean McVay's blossoming coaching tree and will inherit rosters that benefited from the change last season. The Packers in particular have produced positive rushing DVOA totals from single-back formations for three straight seasons.
The Panthers didn't change their ratio of one- and two-back carries, but they enjoyed the biggest boost in success on runs with a single back. Christian McCaffrey is tailor-made to create run-pass uncertainty when he is alone in the backfield. Norv Turner clearly agreed, as evidenced by the team's 20.8 percent increase in plays with 11 personnel. The Panthers had massive improvements of 1.5 yards per carry and 35.6% DVOA from single-back formations from 2017 to 2018. The Seahawks weren't far behind with 1.4 yards-per-carry and 32.1% DVOA improvements on single-back carries in their first season with offensive coordinator Brian Schottenheimer.
With all the momentum building for single-back formations, it was odd to see three teams shift dramatically the other way. But the 49ers and Patriots demonstrate that two-back formations can be effective, and all three of the Raiders (24 percent increase), Lions (21 percent), and Cardinals (19 percent) had clear reasons for their changes.
The Raiders finished top-10 in rushing DVOA from two-back formations in 2016 and 2017. However, that success came on 69 combined attempts, and their rushing DVOA from two-back sets fell to -25.2% last year on a more substantial 98 carries. Fullback Keith Smith remains under contract for 2019, but first-round rookie running back Josh Jacobs was a productive receiver at Alabama and is a better fit for 11 personnel than Doug Martin, Jalen Richard, or any of the Raiders' other one-dimensional backs were in 2018.
The Lions and Cardinals were each bottom-five in rushing DVOA from single-back formations in 2017, averaging 3.3 and 3.4 yards on those carries, respectively. Former Lions offensive coordinator Jim Bob Cooter had not had success running with a lone back in any of his first three seasons with the team, so he was likely motivated to try something different. And the Lions' 25th-place finish in rushing DVOA last year was real progress. It was not enough to save Cooter's job, however. His replacement, Darrell Bevell, seems willing to change his approach based on his personnel. He regularly mixed in two-back formations with Marshawn Lynch in Seattle but declined to just 20 and 11 percent usage in 2016 and 2017 after Lynch retired/switched teams. Bevell may continue to rely on two-man formations since rookie Kerryon Johnson averaged an excellent 5.4 yards per carry with fullback Nick Bellore on the field. LeGarrette Blount averaged just 1.8 yards on those carries and is no longer with the team.
The Cardinals publicized their intentions to rely on fullback Derrick Coleman in 2018, but that didn't help returning star running back David Johnson, who averaged 3.5 yards per carry with Coleman on the field and 3.7 yards per carry without him. Of course, the Cardinals had identically poor 3.4 yards-per-carry averages and -28.0% DVOA totals on their single-back carries in 2017 and 2018. Neither approach was likely to pay dividends behind an offensive line that finished in the bottom 10 in adjusted line yards. The Cardinals will likely look very different in 2019 with Kliff Kingsbury calling plays and Kyler Murray under center, and that will hopefully make life easier for Johnson whether the team relies on a fullback or not.