No. 3: Defensive Line Adjusted Line Yards
Football Outsiders has a metric, for either an offensive or defensive line, to measure a unit’s effectiveness for/against both running and passing games.
This metric is called “adjusted line yards,” and it assigns responsibility to the O- or D-line based of a set criteria.
In 2016, the 49ers D-line posted an adjusted-line-yard number of 4.35, which ranked 29th in the NFL. Slightly better against the pass (20th), it’s still apparent San Francisco’s defensive front was a major liability against the run.
Teams knew it too, often electing to run against the 49ers in nickel personnel, which removed run-stopping nose tackles from the formation.
Taking a look at the entire front seven, Pro Football Focus ranked the Niners No. 31 last year. This also isn’t surprising, especially considering former defensive coordinator Jim O’Neil’s “read and react” defense that often left defenders out of position.
This should hopefully change under Robert Saleh, who will look to frontload the box with extra defenders and dish out easier gap assignments to the guys up front.
Also worth noting is the first-round selection of former Stanford defensive end Solomon Thomas who, per PFF, posted better collegiate run-stopping grades than his two D-line predecessors, DeForest Buckner and Arik Armstead:
If Thomas and Co. can help the Niners D-line get into the 4.00 range of adjusted line yards, the defense should end up being in relatively good shape for now.