New Ole Miss defensive coordinator Wesley McGriff has his work cut out for him

There was an understandable mix of hope and excitement as Wesley McGriff was introduced as the Rebels’ new defensive coordinator Friday, partly because it’s somewhat of an outside hire, but also because he’s made a tangible impact pretty much everywhere he’s coached.

After adding McGriff as secondary coach, the Saints’ defense improved from 28th to sixth in Passing DVOA from 2012 to 2013. As co-defensive coordinator, he helped Auburn soar from 34th to seventh in Defensive S&P+ in 2016.

The job he faces in turning around the defense in Oxford, however, goes beyond anything he’s previously faced. Part of that is because his only other true coordinator experience came two decades ago at DII Kentucky State. Part of that is because Dave Wommack’s 2016 defense was really, really bad.

The graphs below show just how bad.

Between 2014 and 2016, Wommack’s unit fell from first to 77th in Defensive S&P+. Unable to make up for roster turnover, the defense couldn’t get off the field for stretches at a time this season, playing nearly 100 more snaps than 2014, which included that extra bowl game that we don’t need to talk about.

In addition to recording more raw snaps, the 2016 defense gave up many more positive plays, and offenses hardly ever experienced prolonged droughts, as opposed to the constant “flatlining” shown in the 2014 graph.

The defense was especially bad when it came to allowing big plays on the ground, ranking 120th in Rushing IsoPPP (a measure of explosiveness). When runners made it to the second level, there was little stopping them from turning the opportunity into a massive gain.

Over the two seasons prior, the biggest single rushing gain allowed was 43 yards. In 2016, Ole Miss allowed nine rushes longer than that. Part of this is on the defensive line, which let runners into the second level 41.3 percent of the time (88th worst nationally), but they didn’t have much help at the linebacker position.

Safeties shouldn’t be the first defenders to touch a running back, but that was the case far too often. The Rebels allowed an astounding 1,948 rushing yards before contact. That’s more than the total rushing yards allowed by 60 other FBS teams.

Here they all are.

Ole Miss’ yards before contact figure (on the far left) is 2.4 times larger than Alabama’s total figure. In summation, this is not good.

The defense’s troubles didn’t stop on the ground, as they had a way of making SEC quarterbacks look like studs. In five of the Rebels’ six conference losses, opposing QBs outperformed their average in-conference passer rating.

While Nick Fitzgerald evolved into a perfect schematic fit for Dan Mullen’s offense thanks to his running ability, he was never that gifted of a passer. That makes his passer rating jump of more than 50 against Ole Miss more than a bit alarming. Vanderbilt’s Kyle Shurmur threw for 9.1 yards per attempt when facing the Rebs, compared to his season average of 6.8.

Wommack’s defenses were always known for their ability to generate chaos and knock teams out of any systematic flow, a trait best characterized statistically by havoc rate: the percentage of plays in which a defense either recorded a tackle for loss, forced a fumble, or defensed a pass. The graph below shows how sharply Ole Miss’ havoc rate dropped off in 2016.

It’s possible that McGriff’s expertise in coaching defensive backs could lend itself to an immediate improvement in havoc rate. The 2015 defense made up for its lack of efficiency by boasting a secondary and defensive line that ranked first and 28th in positional havoc rate, respectively. It’s unlikely that McGriff can turn this group into a shutdown force of nature in less than a year, but resembling that 2015 defense’s ability to occasionally punch offenses in the mouth may be a realistic goal.

Many of the Rebels’ defensive shortcomings can be attributed to poor coaching and player development, such as their issues with giving up explosive plays and constantly being out of position, but other times it simply came down to lacking the bodies to compete in the SEC.

No matter who Ole Miss brought in to coach the defense, there weren’t going to be any immediate fixes. It generally takes at least a year for a new defensive coordinator to fully implement their scheme and make a lasting impact. On top of that, McGriff will have to work with a roster seriously lacking in depth and in some cases, maturity.

Even so, there are areas that must show improvement quickly, and given the low bar that 2016 has set, it’s entirely possible for him to affect change in a short amount of time.