Why didn’t Ohio State pressure the QB more last season?

Conventional wisdom says that the defensive line is not a position the Buckeyes need to worry about very much for 2017. Essentially the entire defensive line returns, including defensive ends Sam Hubbard, Jalyn Holmes, and Tyquan Lewis.

But for as good as the defensive line looked last season, the numbers suggest that there might be a few issues nevertheless. Primarily, that has to do with how effective the defensive line was at pressuring the quarterback.

The Buckeyes ranked 54th in total sacks last year, but were 78th in adjusted sack rate. Was there actually a problem with the defensive line last season? And because the same personnel return, will there be a problem with defensive pressure again this season?

Potential reasons for the low sack rate

1. Talent. Talent is usually cited as a strength for the defensive line, particularly at defensive end. Lewis, Hubbard, and Holmes, the top three at the position, were all four-star recruits.
2. Personnel fit. Is it possible that, while talented, none are pure pass rushers?
3. Scheme. The low sack numbers could be a byproduct of the play calling. For instance, if the defense usually only rushed four, that could largely account for the lower-than-expected sack rate. But even if that’s true, shouldn’t Ohio State-caliber ends be able to get pressure without a big numbers advantage?

Some context

Even the adjusted sack rate, when viewed by itself, doesn’t necessarily tell you a whole lot. So here are some other relative statistics:

Do the Buckeyes have work to do at defensive end?

The picture you get from the other advanced stats is still a little unclear. Overall the pass defense was excellent, ranking eighth overall in passing S&P+. But how much of that is due to an absurd secondary that will likely have three defensive backs drafted, potentially all in the first round?

The issue isn’t with the line’s ability to create havoc overall, either. If you include tackles for loss in the equation, the defensive line ranked 19th in line havoc rate, first in stuff rate (which measures the rate of tackles at or behind the line of scrimmage), and first in power success rate (which measures the effectiveness in short-yardage situations). The line was incredibly effective at generating havoc plays in the run game — it was more or less just an issue with getting to the quarterback.

But there does seem to be some kind of issue with the pass rush. There’s not much of a difference between the pass rush on standard versus passing downs (78th and 90th), but passing downs success rate was poor relative to the rest of the defense’s play (34th). And that’s despite the use of the vaunted Rushman package, which packs the line with four defensive ends.

My guess is that this is an issue with specific personnel assignments and scheme more than any single issue by itself. As you can see from the talent ratings of the top three ends at .9277, it isn’t like there is an overall talent problem. Instead, as Ross Fulton has suggested, it might be more about what these ends are asked to do relative to their overall strengths and weaknesses. It’s possible that none are truly elite pass-rushing specialists, despite them being excellent players overall.

My guess is that one or more of Nick Bosa, Jonathon Cooper, and Chase Young find themselves in the steady rotation at end. These three former five-stars have extraordinarily high ceilings as pass rushers, which will be especially important in 2017 when Malik Hooker and Marshon Lattimore are no longer in the secondary, ready to turn a QB pressure into a pick-six. Assuming that the 2017 secondary doesn’t create the same level of havoc as the 2016 group (which was third in interceptions per game), the defensive line will need to turn more QB pressures into sacks.