There's no getting around it, the Bengals had an incredibly average rushing attack in 2015. They ranked 13th in yards per carry (3.9), 13th in yards per game (112.8), and 31st in runs over 20 yards (five). Despite the passing game really finding its legs under Andy Dalton, the running game suffered because the starter, Jeremy Hill, averaged a measly 3.5 yards per run, which ranks 31st among running backs in the NFL.
It was a bad season from Hill, who started 15 regular season games. The only reason he didn't start all 16 was due to being disciplined for missing a team meeting the day before the San Francisco game. However, Giovani Bernard's impressive season seems to have gotten lost in the shuffle. A big problem with the Bengals rushing game was the fact that Bernard only started one game and took only 154 of the carries, as opposed to Jeremy Hill's 223. Bernard averaged 4.7 yards per carry, which ranked third in the NFL for running backs with at least 154 touches. It would stand to reason that he should have seen more touches to give the Bengals' rushing attack a boost, right?
Based on data from Pro Football Focus's Mike Clay on how defensive packages affected yards per carry in 2015, it seems like an accurate assessment.
Giovani Bernard's strong play was somehow overshadowed by Jeremy Hill's struggles, but Bernard was a significantly-more effective runner. His 4.8 YPC was well above expected, and his 4.9 YPC against base defenses was seventh-best in the league.
According to Clay's numbers, Bernard faced defensive packages that allowing average of 4.3 yards per carry throughout the the season. He improved on that expectation by 0.5 yards per carry, which is tied for the ninth highest in the NFL last year. For running backs with less than 200 carries, he was tied for seventh.
Here are the players who PFF calculated as having a positive "expected" YPC differential (including Bernard).
Here are the players who PFF calculated as having a negative "expected" YPC differential (including Hill).
Hill, on the other hand, significantly fell below his expected yards per carry. He typically faced base defenses that are designed to stop the run, while Bernard typically faced off against nickle and dime packages. However, what matters here is the expected yards per carry. Obviously, against a base defense, the expectation is a bit lower at 4.1.
Hill averaged 3.5 yards per carry when running directly out of the backfield. That's 0.6 yards per carry lower than what was expected, given the defenses he was generally facing. In a cruel reverse of what we saw from Bernard, Hill's expectation vs reality differential ranked the ninth lowest of qualified running backs and dead last out of any running backs with at least 200 carries.
What does this all mean heading into the 2016 season? Hopefully not much. Hill performed incredibly well in his rookie season. You'd like to think it wasn't a fluke and he just had a bit of a sophomore slump. After all, Bernard had a bit of a sophomore slump himself in 2014 that saw him lose his starting position to Hill.
Either way, it seems like the amount of negativity surrounding the Bengals' running game in 2015 was a bit short-sighted. Yes, the team struggled to develop the portion of the offense that helps settle things and allows them to wear down opposing defenses. It became a clear disadvantage when Dalton went down and the team had to start an inexperienced backup quarterback in AJ McCarron.
But, there's still an encouraging sign to be taken away from all of this. The Bengals have one of the most useful running back tandems in the NFL. In 2014, Bernard struggled to consistently produce and Hill stepped in to really get things going. In 2015, Hill struggled and Bernard provided a boost to jumpstart the offense. In 2016, maybe we'll see both running backs settle in and prove effective at the same time, creating a dynamic running game for Cincinnati, like what we expected to see in 2015.