Tennessee Analytics: Defensive Improvement Starts at Line of Scrimmage

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    Photo Credit: Mason Burgin/RTI

    Last week, we discussed how first year offensive coordinator Larry Scott can improve Tennessee’s offense on passing downs.

    In this installment of our analytics series, we move to the other side of the ball.

    Bob Shoop came to Knoxville last fall as one of the most heralded coordinator hires in the country. But no one expected what came next. Shoop’s defense was inconsistent at best in 2016, and it led to a major disappointment.

    The Fremeau Efficiency Index, which is a value generated per possession adjusted for the strength of opponent offenses faced, ranked the Vols’ defense as 65th nationally. But unlike the offense’s failures on first and second down, Tennessee’s defense doesn’t have one glaring weakness according to the analytics.

    It’s just all around average.

    When an opponent got at least one first down, Tennessee gave up a touchdown 37.2 percent of the time. Tennessee’s Touchdown Rate after First Down was 55th in the FBS.

    The problem wasn’t necessarily giving up the big home run play, but stopping the bleeding once the offense moved the chains a couple times. And that starts with controlling the line of scrimmage, which Tennessee didn’t do last year.

    Without Derek Barnett, Tennessee would’ve had one of the nation’s worst defensive lines. Granted, that group was the most banged up of any others on the roster. But the Vols’ D-Line ranked 79th nationally according to the analytics.

    Going back to Tennessee’s game against Florida, without Barnett’s tenacious pass rush in the second half, the Gators probably win. But on third downs like this, and in tight situations when it mattered, the Vols found a way to come up big.

    That’s why UT’s power success rate was 25th in the country. Power success rate is defined as the percentage of plays that take place on 3rd or 4th and 2 or less that result in a first down or touchdown.

    The vast majority of Tennessee’s success defensively last year all started with Barnett. Even when he wasn’t in the picture, he was drawing two or sometimes three blockers, freeing up space for the weak side rusher.

    But Barnett isn’t walking through that door this season. There likely isn’t going to be that much space on the line to rush the quarterback.

    When the Vols’ backs were against the wall, they was good at getting stops. The real damage was done on first and second downs.

    On standard downs (first down, second-and-7 or fewer, third-and-4 or fewer, fourth-and-4 or fewer), Tennessee gave up 3.14 yards per play. That was one of the worst marks in college football, rating as the 91st-ranked standard down rate in the FBS.

    UT’s 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 defensive line does its job, so to speak, was also poor. When an offense had five yards to gain, it was successful gaining the line 40.8 percent of the time, which ranked UT 85th nationally.

    1. So how do you remedy that? Better run defense on first and second down. That’s where opposing teams made the Vols pay last season a majority of the time. That means the Vols’ front seven will have to improve their play in 2017.

    Shy Tuttle and Kahlil McKenzie will be back healthy again, which is a huge boost. The improvement starts with those two, who are ready for big junior seasons. Tennessee has had pressure on the outside, but it needs strength to stop the run on first and second down up the middle.

    When the linebackers are plugging holes up the middle on third and short, Shoop’s defense has no problems. Now UT needs to take the next step at the line of scrimmage under Brady Hoke.

    1 COMMENT

    1. Good analysis and Barnett was extremely important to the defense although not the leading tackler. This years team figures to be more physically fit than last years team and the DL will be deeper…..we shall see.

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