Advanced Stat Breakdown: Clemson has the better defensive line; Alabama has a superior offensive line

Let’s begin the advanced stat comparison with the endgame: Here’s an excerpt of the conclusion from Freeman and Connelly’s exceptional Bowl extravaganza at Football Outsiders:

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Clemson did a lot of their damage this year by getting the ball on the perimeter to burners like running back Travis Etienne (744 rushing yards, 7.2 yards per carry) or receiver Ray-Ray McCloud (542 receiving yards). They can also attack coverage with ultra-shifty slot receiver and two-time Alabama killer Hunter Renfrow or big outside target Deon Cain (659 receiving yards). Quarterback Kelly Bryant is as strong a runner as his predecessor Deshaun Watson, but he's not nearly as good in the dropback passing game. The Clemson offense now relies more on option plays and working the ball down the field rather than picking it up in chunks.

In a close, defensive battle, it's not obvious which team would hold the advantage, but Alabama is generally very good at avoiding turnovers and ranks much higher in special teams. They may hold the overall advantage unless their offense is totally swamped by the Clemson defense.

S&P+ Outright Pick: Alabama

To reach the conclusion that Alabama will contain a Clemson offense absent generational talent Deshaun Watson, FO compares the following rankings:

There’s plenty more preview at that link above; give it a read. But, I wanted to prod a bit deeper into the granular line data — the little battles and team tendencies that aren’t necessarily apparent in a broad index like the S&P+ or FEI.

Here’s how the teams matchup (data and variable operationalization from FO, with some variables paraphrased for ease of apprehension):

Offensive Lines:

These are two teams with big, strong, athletic offensive lines. Both excel at run blocking, but have given up their share of hits in the passing game. But, Alabama does have the advantage in nearly every metric across the line. The Tide are better on standard downs (best in the nation, in fact,) in power football, in preventing stops at the LOS, and they have been much, much better at preventing sacks on standard downs. This will be a matchup to watch: While Clemson’s defensive line excels at pressuring the passer, Alabama’s pass-blocking strength has been preventing sacks on Jalen Hurts in obvious passing situations. And, while the Tigers do some things well, success in power running and protecting Kelly Bryant on obvious passing downs aren’t among them (of course, we’re grading on a curve here.)

Run-blocking

• Adjusted Line Yards: 100.0 is perfectly average, above 100 is good, below 100 is bad.
• Standard Downs Line Yards per Carry: The raw, unadjusted per-carry line yardage for a team on standard downs (first down, second-and-7 or fewer, third-and-4 or fewer, fourth-and-4 or fewer).
• Passing Downs Line Yards per Carry: The same unadjusted averages for rushing on passing downs.
• Opportunity Rate: The percentage of carries (when five yards are available) that gain at least five yards, i.e. the percentage of carries in which the line does its job, so to speak.
• Power Success Rate: ... percentage of runs on third or fourth down, two yards or less to go, that achieved a first down or touchdown.
• Stuff Rate:... percentage of carries by running backs that are stopped at or before the line of scrimmage

Pass-blocking

• Adjusted Sack Rate: An opponent-adjusted version of a team's sack rate -- sacks divided by (sacks plus passes), presented on a scale in which 100 is perfectly average, above 100 is good, below 100 is bad.
• Standard Downs Sack Rate: Unadjusted sack rate for standard downs pass attempts.
• Passing Downs Sack Rate: Unadjusted sack rate for passing downs pass attempts.

Photo by Doug Buffington/Icon Sportswire via Getty Images

Defensive Line

Rushing Stats

These statistics mirror the offensive line data above, with of course the outputs being defensive line effectiveness. Here, the Tide and Tigers do things overall very well, but each unit has its strengths, with the nod going to Clemson overall.

Both teams stuff plays at the LOS with the same frequency, (22%, 39th for each.) And forcing standard-down passing, it’s really six-of-one, half-a-dozen-of-another (Alabama 3rd, Clemson 8th.)

Where the real advantage for Clemson lies is that it is the superior pass-rushing team. Not only do the Tigers lead the nation in sacks, CU is first in both generating sacks on standard downs and overall adjusted sack rate. The Tigers have also been excellent in preventing short-yardage power runs.

As we covered in the Q&A with Shakin’ the Southland, where Clemson has “struggled” is in getting to the quarterback on passing downs. Even then, the Tigers are 21st in the nation in such category. But, as noted above, that is the passing metric that Alabama’s offensive line has been particularly good at. (Don’t forget to check out our questions to Shakin’ right here.)

On the flipside, where Alabama has the overwhelming advantage over the Tigers is in standard down defense and creating obvious passing situations. And, Alabama does an excellent job of both putting opponents into long passing situations and then capitalizing with its most effective pass rushing.

Run-blocking

• Adjusted Line Yards:... 100.0 is perfectly average, above 100 is good, below 100 is bad.
• Standard Downs Line Yards per Carry: The raw, unadjusted per-carry line yardage for a team on standard downs (first down, second-and-7 or fewer, third-and-4 or fewer, fourth-and-4 or fewer).
• Passing Downs Line Yards per Carry: ...The same unadjusted averages for rushing on passing downs.
• Opportunity Rate: The percentage of carries (when five yards are available) that gain at least five yards, i.e. the percentage of carries in which the line does its job, so to speak.
• Power Success Rate: ...percentage of runs on third or fourth down, two yards or less to go, that achieved a first down or touchdown.
• Stuff Rate: percentage of carries by running backs that are stopped at or before the line of scrimmage.

Pass-blocking

• Adjusted Sack Rate: An opponent-adjusted version of a team's sack rate -- sacks divided by (sacks plus passes), presented on a scale in which 100 is perfectly average, above 100 is good, below 100 is bad.
• Standard Downs Sack Rate: Unadjusted sack rate for standard downs pass attempts.

Passing Downs Sack Rate: Unadjusted sack rate for passing downs pass attempts.

Conclusion

The offensive lines aren’t really comparable: Alabama has advantages at nearly every metric. The nod along the defensive line goes to Clemson, but, like your Facebook status — it’s complicated. Conventional wisdom says that the key matchup and deciding factor in the Sugar Bowl will be Clemson’s defensive line versus Alabama’s offense. But, when you’re looking for game-deciding contrasts then great-versus-great isn’t particularly illuminating. Rather, the data suggest that the real battle to watch will be Alabama’s front when Clemson has the ball.

The key for Alabama will be preventing Clemson from getting ahead of the chains. The Tigers’ offensive line is not particularly adept at powering over opponents in these situations. And, while Alabama’s defense has been good at limiting these opportunities for opponents, they’ve been fairly porous and have had a difficult time getting stops in those obvious situations: Putting Kelly Bryant in third-and-long, and then having success on that down, will decide this game.