When Bryce Drew was named Vanderbilt’s head coach in 2016, the first thing I noticed when peeking at his numbers on KenPom was that his last two teams at Valpo were really good defensively.
That’s why it was surprising to see last year’s team struggle mightily on the defensive end. Vanderbilt’s 2017-18 team ranked 219th nationally — and dead last in the SEC — in defensive efficiency. The Commodores were capable of scoring with just about anyone, but they couldn’t stop bleeding points on the offensive end.
There were lots of problems with the defense, but it started with the fact that last year’s defense could not stop opposing teams from getting easy baskets. It’s not quite so simple, but most teams that can’t defend inside the three-point arc are going to have major issues. Last year’s Commodores allowed opponents to shoot 50.7 percent — 209th nationally — on two-pointers. In SEC play, that number went up to 51.4 percent. And while Ken Pomeroy has done quite a bit of work to show that opposing three-point percentage is mostly random, Vanderbilt ranked 295th nationally in that stat, which probably isn’t a coincidence since opponents attempted relatively few threes. If there is an effect that defenses have on three-pointers, a defense that protects the rim well will tend to coax worse three-point attempts; a defense that doesn’t defend the rim well will have the opposite effect. Why shoot a 23-footer when you can drive to the basket and get a layup?
So: all that is to say that through 12 games this season, Vanderbilt’s defense is allowing opponents to shoot just 43.9 percent on twos, good for 20th nationally. Just three opponents — Winthrop, Liberty, and NC State — have managed to shoot over 50 percent inside the arc. Two of those games were played early in the season, and NC State is one of the best teams in the country at making shots. Obviously the competition plays a role — but last year, Kansas State shot 65.8 percent on twos against Vanderbilt and Arizona State shot 58.8 percent. This year, those same teams shot 46.3 percent and 34.1 percent, respectively.
Meanwhile, opponents’ three-point percentage has dropped significantly as well to 31.9 percent. As usual with a stat heavily influenced by randomness, there have been some outlier performances (hi, Kent State), but the general trend is for opponents to have much worse shooting performances than they did last season. And all of this improvement appears to be real, too: Vanderbilt is blocking 12.3 percent of opponents’ two-point attempts this season, up from 8.7 percent last year.
Defense is a lot more personnel-dependent than commonly realized. Last year, Matthew Fisher-Davis has a block percentage of 2.1 percent and that was third on the team. This year, Simi Shittu has a 2.6 block percentage and that’s good for fifth on the team, behind Clevon Brown, Matthew Moyer, Yanni Wetzell, and Aaron Nesmith. (This, by the way, is quite different from the 2015-16 team, which had similar defensive numbers inside the arc but almost all of it came from two players.) Blocking shots isn’t the be-all, end-all, but as a general rule players who are blocking shots are contesting even more.
Now, it would be too simplistic to say that defending the rim is all there is to playing defense. Vanderbilt hasn’t been good at forcing turnovers, ranking 300th nationally, and rebounding could stand to improve. But this also looks nothing like the defense that got lit up in SEC play last year.